G.f.: (2-x)/((1+3x)(1-4x)); e.g.f.: exp(4x) + exp(-3x); a(n) = 4^n + (-3)^n.

A087452

G.f.: (2-x)/((1+3x)(1-4x)); e.g.f.: exp(4x) + exp(-3x); a(n) = 4^n + (-3)^n.

Terms

    a(0) =2a(1) =1a(2) =25a(3) =37a(4) =337a(5) =781a(6) =4825a(7) =14197a(8) =72097a(9) =242461a(10) =1107625a(11) =4017157a(12) =17308657a(13) =65514541a(14) =273218425a(15) =1059392917a(16) =4338014017a(17) =17050729021a(18) =69106897225a(19) =273715645477

External references