G.f.: 1 / (1 + 4*x*G(x)^2 - 7*x*G(x)^3) where G(x) = 1 + x*G(x)^4 is the g.f. of A002293.
A147855
G.f.: 1 / (1 + 4*x*G(x)^2 - 7*x*G(x)^3) where G(x) = 1 + x*G(x)^4 is the g.f. of A002293.
Terms
- a(0) =1a(1) =3a(2) =22a(3) =174a(4) =1444a(5) =12323a(6) =107104a(7) =942952a(8) =8381596a(9) =75053100a(10) =676017962a(11) =6118171326a(12) =55591175956a(13) =506805088026
External references
- oeis: A147855