```{index} single: bnok; Math::GMP function ``` ```{index} single: Math::GMP::bnok; Perl function ``` # bnok Return the binomial coefficient `$n choose $k`. ## Synopsis ```perl my $x = Math::GMP->new(5); print $x->bnok(2); # 10 ``` Equivalent to `$n! / ($k! * ($n - $k)!)`, but computed without building the factorials — suitable for counting problems where `$n` is large.