Function: binomial
Section: number_theoretical
C-Name: binomial
Prototype: GL
Help: binomial(x,y): binomial coefficient x*(x-1)...*(x-y+1)/y! defined for
 y in Z and any x.
Doc: \idx{binomial coefficient} $\binom{x}{y}$.
 Here $y$ must be an integer, but $x$ can be any PARI object.
Variant: The function
 \fun{GEN}{binomialuu}{ulong n, ulong k} is also available, and so is
 \fun{GEN}{vecbinome}{long n}, which returns a vector $v$
 with $n+1$ components such that $v[k+1] = \kbd{binomial}(n,k)$ for $k$ from
 $0$ up to $n$.
