Maple V, release 4 (PowerMac version).
I got a strange sum the other day...
> sum((k-2)*x^k/k!,k=0..infinity); exp(x) orthopoly[L](1, -3, -x)
But Maple does these two fine:
> sum(k*x^k/k!,k=0..infinity); x exp(x) > sum(2*x^k/k!,k=0..infinity); 2 exp(x)
It seems to be a bug in orthopoly package...
> with(orthopoly): > L(1,1,x); -x + 2 > L(1,a,x); 1 + a - x > L(1,-3,x); L(1, -3, x) ???????? > L(1,-3.0,x); -2.0 - x
It is corrected with Maple 7. (U. Klein)