procedure main ()
    every  n := 1 to 10 do {
	write (n, "! = ",  memoized_factorial ( n ) );
    }
    n := 135; write(n, "! = ",  memoized_factorial ( n ) );
    n := 155; write(n, "! = ",  memoized_factorial ( n ) );
end
procedure memoized_factorial ( k )
    static results;
    static k_limit;
    static k_old;
    initial {
	results := [1];
	k_limit := 10 ^ 5;
	k_old := 1;
    }
    if (k < k_limit) then {
	while (k > *results) do results := results ||| list(*results)
	every n := (k_old + 1) to k do {
	    results[n] := n * results[n - 1];
	}
	k_old := k;
	return results[k];
    } else {
	return ((k / &e) ^ n) * sqrt(2 * &pi * n);
    }
end