> Sequences http://www.research.att.com/~njas/sequences/A001835 (a(n) = 4a(n-1) - a(n-2); a(0) = a(1) = 1) and http://www.research.att.com/~njas/sequences/A079935 are the same, except for a initial extrra 1. Me: Yes, true. I will add comments to emphasize that these are two versions of essentially the same sequence. Best regards Neil