Questions tagged [integer-sequence]

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3
votes
1answer
210 views

Solve transcendental equation involving a built-in function [closed]

How can I solve an equation of the following form? $$x = 10+\mathrm{\mathbf{PrimePi}[x]}$$ where $x$ is an integer. I am using Solve but am getting the following ...
1
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0answers
38 views

Finding sequence limits from matrix determinants

I have a problem whereby I want to calculate the limit of a sequence of determinants of matrices of increasing dimensions using the DiscreteLimit command. To illustrate this, I use an example with a ...
0
votes
1answer
76 views

Solving an equation in integers giving an errormessage

I've the following code: ...
2
votes
1answer
35 views

Generating number sequence

I am very new to mathematica. I am trying to generate list of number sequence. I want to make 6 sequences. 1 - 10, 10 - 100, 100 - 1 000, 1 000 - 10 000, 10 000 - 100 000. All reversed. Is there any ...
0
votes
0answers
93 views

Accessing internal calculations of Mathematica code

For a given Mathematica program that generates a sequence x of integers, is it possible to also generate equal length sequences of integers that were used internally by the Mathematica kernel to ...
3
votes
2answers
193 views

solve for two variables for each n related to Collatz conjecture

For this code, for each x I would like to solve for all value ranges for c1 and c2 in a bounded range ie c1 and c2 in the range of real numbers +-100 for c1 and c2 for each x, which combined give "...
1
vote
1answer
193 views

Finding recurrence formulas from procedural code and output lists associated with integer sequences

This code outputs 37 sequences and takes about 15-minutes to run. I would like to be able to see how many and which variables { i, j, k, m, n } each of the 37 ...
8
votes
5answers
313 views

Return last number in sub-sequences in a list of integers

Given a list of integers like this: z = {113, 117, 118, 119, 120, 121, 475, 476, 529, 538, 542, 543, 544} I want a function that returns: ...
1
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0answers
116 views

Integer sequence and RAM limits [closed]

I am trying to calculate the set of unique differences in a sequence, however the sequence grows fast and I hit the RAM limit of my PC for nthPrimeToUse = 11. For nthPrimeToUse 1 to 10 the output of ...
22
votes
4answers
1k views

Generate and graph the Recamán Sequence

I was surprised to see that we don't have any posts that mention the Recamán Sequence, so I figured I should post it as a challenge. By definition, $a_0=0$ and $a_n=a_{n-1}-n$ if the r.h.s. is ...
6
votes
4answers
852 views

RandomInteger with equal number of 1 and -1

I want to generate a list of random integers with only three values 1,0,-1. I know it can be done through RandomInteger[{-1, 1}, n]. How can I impose constraint on this list so that every integers in ...
2
votes
2answers
105 views

Mathematica analog to Wolfram|Alpha dataset analysis [closed]

I have a set of sequences with length 8,48,480,5760,.. and would like to do sequence analysis on them. I plugged the length 8 sequence into wolframalpha: https://www.wolframalpha.com/input/?i=11,+2,+...
4
votes
1answer
104 views

Something is wrong with the implementation of the ThueMorse function

While trying to answer this Math.SE question, I believe I found several bugs in Mathematica and Alpha relating to the Thue-Morse sequence. As a quick reminder, the $n^{\rm th}$ element of the Thue-...
1
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0answers
36 views

Find all integer tuples in a bounded region

For given rational numbers $p_1/q_1,p_2/q_2,p_3/q_3$ and a negative integer $d$, I'd like to find quadruples of integers $(w,x,y,z)$ in a rectangle(of particular sidelengths) satisfying the series of ...
3
votes
1answer
62 views

FindGeneratingFunction gives up too easily [closed]

I am trying to automatically find a generating function from the coefficients of a simple rational function using Mathematica's FindGeneratingFunction: ...
2
votes
1answer
134 views

Constructing the following figure using mathematica

How do I construct the figure in the image using the formulae in Mathematica? I defined the following functions for the 4 cases. Can you also explain the significance of these in relation to the ...
10
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2answers
780 views

How to construct rectangular figures from the Fibonacci numbers?

How do you construct rectangular figures ("golden rectangles") using the Fibonacci numbers in Mathematica using graphics? I know that the basis of the construction of these figures are the formulae ...
0
votes
1answer
67 views

How to postulate a formula for the following Mathematica function

I am using Mathematica to explore the properties of the Fibonacci Sequence. Below is the functions I have defined ...
3
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1answer
85 views

how to obtain these increasing integers for given n and m?

Let n and m be natural numbers. Then, how does one write a function ordint[n,m] that gives ...
3
votes
1answer
101 views

Guess Diophantine equation from its solutions

Take for example the equation $$ n^2=x^2+y^2+1 $$ where $x,y$ are integers. This equation admits solutions only for some values of $n$, to wit, $$ n=1,3,9,17,19,33,35,51,73,81,99,\dots $$ Can we ...
1
vote
1answer
93 views

Is there a way to exclude certain numbers in a sequence?

For example, the sequence of triangular numbers can be expressed as $1/2 [n (n + 1)]$ with $n=1,2,3,4,...$ but is it possible to create a summation of everything remaining $(2,4,5,7,8,9,11,12,13,14,......
5
votes
1answer
70 views

The next element can be obtained using Predict or SequencePredict?

I want to estimate the next number with the data of the sequence listed as elements 0 and 1. For example, when data = {0,0,1,1,0,0,1,0,0,1,1,0,0,1} (actually, ...
5
votes
3answers
123 views

How to find a list of values of recurrence equation?

I tried with RSolve,but it fails: RSolve[{x[n + 1] == n + Sum[j*x[j], {j, 1, n}], x[1] == 1}, x[n], n] Returns unevaluated ...
0
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1answer
49 views

A problem of a sequence and its sum

{a(n)} is such a sequence, satisfying, For all a(i) ∈ {a(n)}, a(i) =1 or -1 Let S(j) = Sum[a(i) , {i ,1, j}], then for all 1<=j<=n ,S(j)>=0. For a given n , how many {a(n)} are there?
1
vote
1answer
68 views

How to perform this indefinite sum?

The following indefinite sum with (CC[n]=1 for even n and CC[n]=i for odd n) ...
2
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2answers
394 views

splitting integer problem

I want to cut the integer into small numbers and show me all the possibilities. For example, if I choose integer 6, then I would like to know how many combination of a 5 dimensional vector (or table ?)...
6
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2answers
95 views

Selecting integers which are not a member in an ordered list of integers

I have an ordered list of integers, i.e.: list = {1,3,5,6,8,10,12,15}; and I want to know if there is a fast way to get a list of the integers that do not appear ...
9
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5answers
673 views

How to tell Mathematica to do this with decimal part of real number?

My apologies if this was asked here before. My friend and I want to do this: Suppose that we have some real number $a. a_1 a_2...a_n...$ where $a_i$ are digits in the set $\{1,2,3,4,5,6,7,8,9,0\}$ (...
1
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0answers
60 views

Coefficients of polynomials forming an unimodal sequence

Let $f(x)=\sum_{i=0}^{n}a_{i}x^{i}$ be a polynomial with rational coefficients. I am interested in an efficient way which allows checking whether the finite sequence $A=(a_{i})_{i\in\{0,\ldots,n\}}$ ...
0
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2answers
459 views

How do I graph only integers using the list function?

I have plotted the following function using the following code: ...
2
votes
1answer
113 views

efficiently method for generating a sequence

The sequence is defined as $a(1)=1,a(n)=a(n-1)+a\left(\left\lfloor \log _2(n)\right\rfloor \right)$ A natural way do this is ...
3
votes
1answer
547 views

Evaluate large Fibonacci numbers

I want to evaluate that Fibonacci[28143753246]. However the result is OverFlow[]. Is there any way to evaluate it? Thank you.
2
votes
3answers
155 views

Finding the largest palindrome which is the product of two 2-digit numbers

My goal is to find the largest palindrome which is the product of two 2-digit numbers using the following program. I want the program to add each palindrome it finds, to the list H. I also want it to ...
4
votes
1answer
107 views

Simplifying/re-expressing a generating function for an integer sequence using Mathematica

Consider the sequence of natural numbers generated by: $f(n) = 2 n + (-1)^n/2 - 1/2$, for $n > 0$ and $n \in \mathbb{Z}^+$ (positive integers): i.e., {1, 4, 5, 8, 9, 12, 13, 16, 17, 20, ...} ...
2
votes
2answers
90 views

Producing a particular sequence of integers recursively [closed]

I am supposed to write a function which computes the next integer in a sequence from the given one. For example: nextval[57] should give mm ...
0
votes
0answers
74 views

PARI to Mathematica conversion

I need to use the coefficients T(n,k) in my algorithm and I found a program in PARI Can anybody translate this code to mathematica? ...
3
votes
1answer
156 views

How many terms does FindSequenceFunction need to discover a simple polynomial rule?

Consider a simple sequence starting with seq1 = {429, 1014, 1935, 3264, 5073, 7434, 10419, 14100, 18549, 23838}; We are looking for a rule (of course there ...
20
votes
3answers
865 views

Partitioning a number into consecutive integers

Consider n=45; then $$1+2+3+4+5+6+7+8+9=45$$ $$5+6+7+8+9+10=45$$ $$7+8+9+10+11=45$$ $$14+15+16=45$$ $$22+23=45$$ Question: how to find all representations of a ...
1
vote
1answer
93 views

Why does the FindSequenceFunction command sometimes succeed with subsequences, while failing for the longer sequences?

I've encountered this phenomenon a number of times--and can provide specific examples if requested. For example, I have a 75-long sequence of rational numbers for which the FindSequenceFunction fails ...
6
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1answer
112 views

Are there different Method options that can be used with FindSequenceFunction?

The help page states that Method is an option to use with FindSequenceFunction, but I don't find any further information. (There ...
11
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0answers
234 views

Find sequence of sequences?

There is a function FindSequenceFunction in Mathematica, that can identify a sequence of integers based on a few first elements. But what if I have a set of finite ...
13
votes
4answers
4k views

How to implement recursive function

I'm trying to do the following (taken from an answer by Watson to my question on Math SE): Start with $x_1=2$, say. Then define $$x_{n+1} = |\{i \in \{1,\dots,n-1\} \;:\; x_i=x_n\}|$$ i.e. number ...
1
vote
1answer
244 views

How to define amazing Goodstein's sequence?

There is an amazing and counterintuitive theorem: For all $n$, there exists a $k$ such that the $k$-th term of the Goodstein sequence $G_k(n)=0$. In other words, every Goodstein sequence ...
0
votes
1answer
354 views

How to sum over half integers? [closed]

I have an expression of the form Sum[1 + x^n + x^(n^2/2), {n, 0, 10}] but I want to sum over half integers, that is, I require that $n \in \mathbb{Z}+\frac{1}{2}$ ...
1
vote
2answers
407 views

Find the Kimberling Sequence

How to find the Kimberling Sequence by using Mathematica? each row is obtained from the previous by boxing (and expelling) the main diagonal element, and then reading the first number after the box,...
3
votes
1answer
115 views

The permutation of given number sequence that has specific correlation with another

I am interested in the relationship between the Pearson correlation coefficients and the permutations of two random number sequences. An initial Mathematica study is as below: ...
6
votes
3answers
313 views

Find the number of $n$ such that $n!$ is a sum of three squares

I want to check the following theorem by using Mathematica: $\textbf{Theorem} $. $\text{The estimate}$ $\# \{n \le x:n! \text{ is a sum of three squares}\}=7x/8+O(x^{2/3})$ $\text{holds.}$...
2
votes
1answer
100 views

Unexpected behavior of FindGeneratingFunction

FindGeneratingFunction will give up to computer sometimes?Such as FindGeneratingFunction[{1, 4, 6, 4, 1}, x] But actually the ...
3
votes
0answers
55 views

Prepending a sequence with zeros gives `FindGeneratingFunction` hard time

Asking for FindGeneratingFunction[{1, 3, 11, 43, 171, 683, 2731, 10923, 43691, 174763}, t] gives the answer (namely ...
4
votes
3answers
427 views

Opposite Collatz Conjecture

I'm trying to explore what would happen if you change the collatz conjecture to flip the equations for odds and evens. So if you have an even number you multiply by 3, add 1, and divide by 2. If you ...