G.f. satisfies A(x) = 1 + x*(1 + x*A(x)^2)^6.

Terms

a(0) =1a(1) =1a(2) =6a(3) =27a(4) =158a(5) =981a(6) =6342a(7) =42728a(8) =295008a(9) =2079882a(10) =14908740a(11) =108312873a(12) =795836544a(13) =5903472999a(14) =44151306690a(15) =332552305818