G.f. A(x) satisfies: Sum_{k=0..n} [x^k] A(x)^n = binomial(7*n,2*n).

A244653

G.f. A(x) satisfies: Sum_{k=0..n} [x^k] A(x)^n = binomial(7*n,2*n).

Terms

    a(0) =1a(1) =20a(2) =280a(3) =3521a(4) =42945a(5) =521913a(6) =6379233a(7) =78640740a(8) =978172724a(9) =12270946072a(10) =155139813381

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