G.f. satisfies A(x) = exp( Sum_{k>=1} (-1)^(k+1) * A(x^k) * (3*x)^k/k ).

A363442

G.f. satisfies A(x) = exp( Sum_{k>=1} (-1)^(k+1) * A(x^k) * (3*x)^k/k ).

Terms

    a(0) =1a(1) =3a(2) =9a(3) =54a(4) =270a(5) =1620a(6) =9828a(7) =61884a(8) =397062a(9) =2597508a(10) =17232831a(11) =115722918a(12) =784996434a(13) =5371325217a(14) =37029240315a(15) =256948639344

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