Re: [Reduce-algebra-developers] expansion of gamma function

[Andrey G. G. <A.G...@in...>]

On Sat, 10 Oct 2015, Rainer Schöpf wrote:
> 5: ps(gamma(1+x),x,0);
>
> ***** Recursion too deep in ps!:unknown!-crule
<skipped>

> Something similar happens with the taylor package: It tries to compute the
> taylor series be differentiation, but
>
> df(gamma(x+1),x);
>
> gives
>
> gamma(x + 1)*(psi(x)*x + 1)
> -----------------------------
>              x
>
> which leads to computation of psi(0) and therefore to an error.

Can't

log(gamma(1+x)) = - euler_gamma*x + sum((-1)^n*zeta(n)/n*x^n,n,2,infinity)

be used by taylor and/or tps, to calculate the series for gamma(1+x) as 
the exponent of the known series?

By the way, why, after loading specfn and sfgamma, psi(1) is not 
simpilfied to -euler_gamma?

Andrey