[[[3,3, sub Ack { my($M, $N) = @_; return( $N + 1 ) if ($M == 0); return( Ack($M - 1, 1) ) if ($N == 0); Ack($M - 1, Ack($M, $N - 1)); } return Ack($i,$j); ]]] Function "Ack" (Ackermann's function) copied from Doug Bagley.