[seqfan] Re: Formula syntax from some computer programming language

[M. F. Hasler]

 x$n means x, ..., x
n times, which inside diff() means n-th derivative
(Maple syntax)

On Sunday, February 9, 2014, Alonso Del Arte <alonso.delarte at gmail.com>
wrote:
> Does anyone recognize this syntax?
>
> a(0) = 1, a(n) = subs(x = 1, diff(1/(2-x), x$n)), n = 1, 2... - _Karol A.
> Penson_, Nov 12 2001
>
> I'm guessing it's something calculus, but the dollar sign is really
> throwing me off. It comes from A142, the factorials, the formula field of
> that entry also including Wolfram Mathematica syntax in a contribution
from
> Alex Adamchuk.
>
> Al
>
> --
> Alonso del Arte
> Author at SmashWords.com<
https://www.smashwords.com/profile/view/AlonsoDelarte>
> Musician at ReverbNation.com <http://www.reverbnation.com/alonsodelarte>
>
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