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

Terms

a(0) =1a(1) =1a(2) =2a(3) =8a(4) =35a(5) =163a(6) =808a(7) =4162a(8) =22041a(9) =119325a(10) =657384a(11) =3673394a(12) =20769983a(13) =118610807a(14) =683131766a(15) =3963486380a(16) =23144000681a(17) =135911263309a(18) =802143851323