> It simplifies a bit more, I think. Yes, quite correct Ander. I had: W(2N) = f(N) + 2f(N+1) - 3 which is ... f(N) + f(N+1) + f(N+1) - 3 = f(N+2) + f(N+1) - 3 = f(N+3) - 3 First one to give us a quarter-peal composition of TD Max with all 52 wraps wins a sweetie. MBD