and I'm too dumb to make it work. What is the GF? seq= 1,1,3,6,15,31,73,157,358,784 super' says that T015 coefficients of 1/Sn(z) [[Sn(z) = ordinary generating function]] gives a match with: A078996 (Mohammad K. Azarian) and A084610 (Paul D Hanna) I tried my best, but no go! help ? W.