G.f. C(x) satisfies: C(x) = x + 3*A(x)*B(x), where A(x) = x + B(x)*C(x) and B(x) = x + 2*A(x)*C(x).

A229813

G.f. C(x) satisfies: C(x) = x + 3*A(x)*B(x), where A(x) = x + B(x)*C(x) and B(x) = x + 2*A(x)*C(x).

Terms

    a(0) =1a(1) =3a(2) =9a(3) =45a(4) =225a(5) =1275a(6) =7389a(7) =44745a(8) =276849a(9) =1750275a(10) =11236833a(11) =73114437a(12) =480936033a(13) =3193267467a(14) =21372274341a(15) =144040951953a(16) =976706321121

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