Function: prodnumrat
Section: sums
C-Name: prodnumrat
Prototype: GLp
Help: prodnumrat(F,a): product from n = a to infinity of F(n), where F-1
 is a rational function of degree less than or equal to -2.
Doc: $\prod_{n\ge a}F(n)$, where $F-1$ is a rational function of degree less
 than or equal to $-2$.
 \bprog
 ? prodnumrat(1+1/x^2,1)
 %1 = 3.6760779103749777206956974920282606665
 @eprog
