in reply to recursive formula.

Should be something like

sub p { my @args = @_; # for clarity, more efficient not to copy # initializing this handles the zero argument case my $result = 0; $result += ($args[$_] - ($_ ? $args[$_-1] : 0)) * p(@args[0..($_-1)],@args[($_+1)..(@args-1)]) foreach(0..(@args-1)); return $result; }
note: untested

Ron Steinke rsteinke@w-link.net