G.f. A(x) satisfies A(x) = 1/( 1 - x*(A(x) + A(3*x))/2 ).

A385622

G.f. A(x) satisfies A(x) = 1/( 1 - x*(A(x) + A(3*x))/2 ).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =20a(4) =321a(5) =13847a(6) =1718124a(7) =630600310a(8) =691143519765

External references