Questions tagged [digits]
Questions dealing with the manipulation of the digits of numbers, including the functions RealDigits and IntegerDigits.
37
questions
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DigitCount[], but in negative bases
The DigitCount[n,b] function "counts the gives a list of the numbers of $1, 2, \ldots, b-1, 0$ digits in the base-$b$ representation of $n$".
I want to ...
- 967
4
votes
2
answers
94
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Test if the decimal digits of $n$ appear $n$ times in the decimal representation of $n!$
I want to find numbers $n$ for which the decimal digits of $n$ appear $n$ times in the decimal representation of $n!$.
For instance, $n\in\left\{0, 1, 1170, 1528, 9877, 9886, 9897, 11535\right\}$ are ...
- 1,941
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vote
0
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65
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Extracting digits of a real number with RealDigits produces unexpected result
I have a list of real numbers, each of which has two decimal places. I'm trying to extract the second digit after the decimal point.
The function I'm using is ...
- 1,291
1
vote
3
answers
70
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Digits product and an iteration process
I would like to create a code which gives me the square of the product of the digits of a number, with the only rule that if a number has a 0, then it doesn't count in the product (for example, if the ...
- 239
4
votes
4
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74
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How to create a function that merges the first $n$-digits of each value in a list?
Suppose we have a list of numbers. For example,
A={1231,1232,1233,1241,1236}
Using a function f[x,A], I want to rearrange this ...
- 39
3
votes
1
answer
297
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How do I force mathematica to output more digits for this particular expression? [closed]
I'm working on a project where a certain calculation of $\pi$ to an arbitrary precision is required. I'm evaluating the below expression in Mathematica:
$6\sum_{k=0}^{\infty}\left(\frac{\left(-0.5\...
- 31
0
votes
0
answers
51
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How do I increase an amount of digits after the point?
I have an expression such as:
Log[0.784637, 517.8796]*ArcTan[-1.112673]*0.4256^(-2.034)*Sqrt[3.567]
and I get 3 digits precision. I tried:
...
0
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0
answers
100
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How to copy and paste numbers with "`" mark and use them in calculations, without using N or setting precision every time
Suppose we have run a calculation and get a number like
2.758952615889003`
If we then copy-paste this number and do a calculation like
...
- 789
11
votes
3
answers
2k
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How can I program the last digits of Fibonacci numbers?
Is there a way to compute the last digits of an arbitrarily large Fibonacci number?
For the $10^n$th Fibonacci number, we can just find the $2^n$-th Fibonacci number (if that isn't too large) $\bmod n$...
- 333
2
votes
1
answer
191
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Listing numbers whose digit sum is greater or equal 5
I just started using Mathematica and at the moment I'm learning some things.
As you can see in the headline, I want to make a list of numbers (up to 100) whose digit sum is greater or equal 5.
I ...
- 23
3
votes
1
answer
74
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About a problem with FromDigits
I have tried FromDigits[{{1, 2, 3, 4},{2,3, 4, 1}, {3, 4, 1, 2}, {4, 1, 2, 3}}] and the result is as expected {1234,2341,3412,4123}. However for ...
- 31
4
votes
1
answer
134
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Consider all numbers, from two-digit up to 10-digit, written only with digits 1, 2, 3, 5, 7. Identify those that are perfect squares
Consider all numbers, from two-digit up to 10-digit, written only with digits 1, 2, 3, 5, 7. Identify those that are perfect squares
I got this problem but don't know how to solve it. This is what I ...
- 287
4
votes
1
answer
122
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Correcting nonsense digits during data import
I import large amounts of data, and for whatever reason the data in cases add large numbers of either '0s' or '9s'. However, as the numbers have very different relevant digits, I cannot simply use ...
- 1,854
1
vote
2
answers
125
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Generate a sequence of primes giving position and value of a digit in its digit-decomposed version
The prime sequence starts:
...
- 199
2
votes
3
answers
123
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prime number digits less than n? [closed]
How can I ask mathematica to sieve with only primes with three-digit less than a given number. Thank you
for instance I want to find the prime factor of 1337. Thank you
1
vote
1
answer
50
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Constructing 'instrument error' or flooring a number to the last decimal digit
So I have a really sample task i would love to solve without things getting overly (and unnecessarily) complex.
I have a list of imported data coming from some instrument measurements in the form:
{...
- 83
9
votes
3
answers
2k
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How Create a list of the first 10,000 digits of Pi and sum it?
I need help for a problem I m having trouble with.
I need to create a list with the first 10'000 digits of Pi and sum the digits 259 to 7233.
I managed to create a list with the following code:
list1 ...
user63037
6
votes
1
answer
159
views
Extracting binary digits of machine precision numbers
Currently, I am developing an octree data structure. And I need it to be fast. To this end, I would like to have a fast way to extract the $m$ binary digits "after the dot" of each entry in a matrix ...
- 104k
2
votes
2
answers
157
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How to avoid this type of change of digits in computed numbers?
Is there a way to avoid the digits being changed?
...
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0
answers
70
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Generating a list of 4-digit integers by simulating four dice being thrown eight times
I simulate throwing four dice and merge their values together to form a 4-digit number. This is done eight times and I want to get a list like this one:
...
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1
vote
2
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225
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Listing all monotone binary functions
A monotone binary function is defined as follows:
Given binary vectors $\bf x$ and $\bf y$ (each having $n$ bits) with $\bf x\geq \bf y$, a function $f:\bf x\rightarrow\{0,1\}$ is called monotone if $...
- 2,445
2
votes
2
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141
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Listing all monotone increasing binary digits
For $n=5$, I have $32$ binary digits and for this there are $2^{32}$ combinations. Out of this many, the interesting ones (i.e., the ones that have monotone increasing binary digits) are only about "$...
- 2,445
1
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1
answer
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How to find the number of digits in a number
IntegerLength[n] will return the number of digits in an integer.
I could not find a corresponding function that worked for reals, so I wrote my own function, ...
- 93
4
votes
1
answer
256
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Listing numbers with non-repeating digits
I tried to search this but could not find. Given a number of digits(the maximum being 0 to 9), how can I generate a list of all possible numbers without repeating the digits in each number? e.g. Given ...
- 43
8
votes
3
answers
554
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How to write an array of repeated numbers as a single number
Let's say we have a random number consisting of an arbitrary number of digits, such as for example 3097.
This number can be represented as an array of repeated numbers with Mathematica by typing
<...
- 311
1
vote
1
answer
161
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Calculate 40 digits of the MRB constant
MRB constant is the upper limit point of the following sequence
$$s_n=\sum_{k=1}^{n} (-1)^k k^{\frac{1}{k}}$$
$MRB=\color{blue}{0.1878596}...$
I tried to calculate first few digits:
...
- 8,868
1
vote
2
answers
83
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forward or backward IntegerDigits in pairs must yield different results
I have some pair configurations same as {0,1,1,1,0,1} with {1,0,1,1,0,1} or {1,1,0,1,0,1,1,1}...
- 1,503
0
votes
0
answers
44
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Unpredictable behavior of numerical error
A comparison of float calculation and exact expression for
NumberForm[0.3^2 - (3/10)^2, 18]
gives an exact zero for $0.3$.
However,
...
- 1,567
2
votes
3
answers
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Values of sequenced IntegerDigits lists with two fixed elements
How can we access to all values of an IntegerDigits list with a special condition. This restriction is the locality of 0 or <...
- 1,503
8
votes
3
answers
194
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Integer to Alpha Representation [duplicate]
I wanted a nice way to convert natural numbers to alphabetic representations like:
...
- 46.6k
5
votes
4
answers
471
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How do I get this recurrent sequence to show?
What exactly am I doing wrong? The dsf function takes the digits of n, raises them to their own power, then adds them together.
Here is my dsf function.
...
- 373
11
votes
2
answers
760
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Calculate $140$ digits of Conway's Constant from the Look and Say Sequence
The look-and-say sequence is the sequence of numbers $1, 11, 21, 1211, 111221, 312211, …,$ in which each term is constructed by “reading” the previous term in the sequence. For example, the term $1$ ...
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7
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1
answer
293
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Convert real number to IBM 32 Float (not IEEE)
How can I convert real number to IBM 32 Float?
I think how to do it with RealDigits[], IntegerDigits[] and ...
- 516
1
vote
2
answers
127
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How can I Influence the number of digits when printing a polynomial expression or when I want to make it a String?
I have an expession (it is the result of Fit) but I want to print or display an abbreviated form with all numbers in it rounded to say 6 decimal digits.
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1
vote
1
answer
61
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Convert numerical solution to RealDigits
It can be determined that Solve[Gamma[x] == 2*Sqrt[Pi], x] yields a solution of x as ...
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4
votes
1
answer
147
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Sum of squared digits returns incorrect result
For the sake of practicing writing code, I've given myself an exercise in writing a script that checks whether a given positive integer is happy, i.e. take the digits of a number, square them, and add ...
- 1,581
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0
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N[variable,2] displays 6 digits [duplicate]
The following code doesn't behave as I expect. Rather than getting 2 digits upon varying r, I get the default value of 6 digits. What's up?
...
- 1,156