Expansion of g.f.: (1+x)/(1-7*x).

Terms

a(0) =1a(1) =8a(2) =56a(3) =392a(4) =2744a(5) =19208a(6) =134456a(7) =941192a(8) =6588344a(9) =46118408a(10) =322828856a(11) =2259801992a(12) =15818613944a(13) =110730297608a(14) =775112083256