Consider the algorithm: x, y = 1, 2 repeat: print x x, y = x + y, x//y + 1 The assignment is simultaneous and x//y means floor(x/y). This leads to: 1, 3, 4, 8, 10, 15, 18, 24, 28, 35, 40, 48, 54, 63, 70, ... Can you contribute a combinatorial interpretation of this sequence? Cheers, Peter