G.f.: 1 / (1 + 6*x*G(x) - 7*x*G(x)^2), where G(x) = 1 + x*G(x)^3 is the g.f. of A001764.

A226751

G.f.: 1 / (1 + 6*x*G(x) - 7*x*G(x)^2), where G(x) = 1 + x*G(x)^3 is the g.f. of A001764.

Terms

    a(0) =1a(1) =1a(2) =9a(3) =48a(4) =289a(5) =1761a(6) =10932a(7) =68664a(8) =435201a(9) =2777763a(10) =17829489a(11) =114968052a(12) =744178716a(13) =4832624044a(14) =31469746632a(15) =205422018288

External references