f[x] := 2 + 2^x + 1/2 2^x (-1 + 2^x) + 1/6 2^x (-2 + 2^x) (-1 + 2^x) + 1/24 2^x (-3 + 2^x) (-2 + 2^x) (-1 + 2^x) for n = 0 to 10 println[f[n]]