A series evaluation

I have used Mathematica 9.0 to evaluate the series
Sum[2^n/CatalanNumber,{n,0,Infinity}]
that appeared as a question in an issue of the
American Mathematical Monthly.

I need to know how Mathematica finds the sum.

Thanks.

Sum[2^n/CatalanNumber,{n,0,Infinity}]

does not converge. Is that the expression that you were intending to write?

You also may want to read this:

[The Internals of the Wolfram System—Wolfram Documentation

G](The Internals of the Wolfram System—Wolfram Documentation)enerally Mathematica uses a variety fo algorithms to get to its answers -- many of which are not the way a person computing by hand will approach a problem.
(I see from your website that you most certainly know this! So, I am leaving this comment in for others that may stumble on this question… :wink: )

He means

In[87]:= Sum[2^n/CatalanNumber[n], {n, 0, Infinity}]

Out[87]= 1/2 (10 + 3 \[Pi])

The editor chopped the square brackets.
But how MMA does it, that I don’t know.
Best,
David

Yes, I just realized that the expression was the one you mentioned. If one does not use the code formatting tools things like that happen. For example here I write

f[x]

but in line it comes out as f even though I actually did type it in with the brackets and the x. It’s a bug in the community.wolfram.com interface.

Yes -- I suspect the editor is looking for formatting codes of some kind. But it would be better I think to just have a vanilla flavored editor for text.