a(n) = [x^n] G(n,x) where G(n,x) is the n-th iteration of G(1,x) = x/(1-x+x^2), so that G(n,x) = G(n-1, G(1,x)) with G(0,x)=x.

A242574

a(n) = [x^n] G(n,x) where G(n,x) is the n-th iteration of G(1,x) = x/(1-x+x^2), so that G(n,x) = G(n-1, G(1,x)) with G(0,x)=x.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =26a(4) =155a(5) =1225a(6) =12411a(7) =156416a(8) =2388060a(9) =43159172a(10) =905135396a(11) =21655104900a(12) =582527203011

External references