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;
}

[download]
note: untested

Ron Steinke rsteinke@w-link.net

In reply to Re: recursive formula. by rsteinke
in thread recursive formula. by BioGeek

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