On Tue, Apr 29, 2008 at 10:56 AM, Michel Talon <talon at lpthe.jussieu.fr> wrote:
> (%i1) load (zeilberger);
> (%i5) GosperSum (m*(n-m+1)*(n+m-2)/2,m,0,n);
>
> Division by 0
Try simplify_sum, which tries several methods.
load (simplify_sum);
simplify_sum (sum (m*(n - m + 1)*(n + m - 2)/2, m, 0, n));
factor (ratsimp (%));
=> (n-1)*n*(n+1)*(n+2)/8
HTH
Robert Dodier