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

A382920

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

Terms

    a(0) =1a(1) =3a(2) =21a(3) =160a(4) =1320a(5) =11511a(6) =104451a(7) =976317a(8) =9337182a(9) =90937403a(10) =898861308a(11) =8994246132a(12) =90932043400a(13) =927452701605

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