# Recursively calculate triangular number of n
rec n = triangle (int.sub n 1);
triangle n = int.eq? n 1
        1
        (int.add
            n
            (rec n));

triangle 500;

# Recursively calculate factorial of n
factorial n =
    int.eq? n 0
        1
        (int.mul n (factorial (int.sub n 1)));

factorial 20;