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According to Wikipedia - Struve function: Relation to other functions the WeberE function should return this, if the first argument is a negative integer:

$$ \mathbf{E}_{-n}(z) = \frac{(-1)^{n+1}}{\pi}\sum_{k=0}^{\left \lfloor \frac{n-1}{2} \right \rfloor} \frac{\Gamma(n-k-\frac{1}{2}) \left (\frac{z}{2} \right )^{-n+2k+1}}{\Gamma \left (k+ \frac{3}{2} \right)}-\mathbf{H}_{-n}(z) $$

But in Wolfram language it only returns a formula with an alternating sign from the corresponding positive integer argument?

>> Table[WeberE[n, z], {n, 1, 10}] == Table[(-1)^n*WeberE[n, z], {n, -1, -10,-1}]

True

Is the WeberE function for negative first integer argument defined different from the Wikipedia definition?

Update: the Wikipedia equation is edited now. See below

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  • $\begingroup$ I not a expert in this case but Relations Between Anger's and Weber's Function is:WeberE[-n, x] == Cos[n Pi] WeberE[n, x] - Sin[n Pi] AngerJ[n, x] .Maybe this series is wrong and Mathematica gives correct answer. $\endgroup$ Commented Apr 15 at 16:58
  • $\begingroup$ Relations Between Anger's and Weber's Function you can find in the book: personal.math.ubc.ca/~cbm/aands/abramowitz_and_stegun.pdf 12.3.4 on page: 498 $\endgroup$ Commented Apr 15 at 17:06
  • $\begingroup$ The question is about the relation to the StruveH function. The definitions from 12.3.6 and 12.3.7 seem to be the same as in Wikipedia. $\endgroup$
    – axelclk
    Commented Apr 15 at 17:16
  • $\begingroup$ So I was right,in my comment. $\endgroup$ Commented Apr 16 at 4:57

1 Answer 1

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There is a mistake on Wikipedia the upper bound in the sum should be Ceiling[(n - 3)/2]}] instead of Floor[(n - 1)/2]. Please correct the Wikipedia page.

z = Sqrt[3];
N[Table[WeberE[-n, z] == (-1)^(n + 1)/π Sum[(Gamma[1 n - k - 1/2] (z/2)^(-n + 2 k + 1))/
      Gamma[k + 3/2], {k, 0, Ceiling[(n - 3)/2]}] - 
    StruveH[-n, z], {n, 1, 10}], 10]

{True, True, True, True, True, True, True, True, True, True}
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