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

A231554

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

Terms

    a(0) =1a(1) =6a(2) =54a(3) =588a(4) =7116a(5) =92016a(6) =1244928a(7) =17405520a(8) =249486480a(9) =3646632288a(10) =54146466528a(11) =814458834432

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