A367048 G.f. satisfies A(x) = 1 + x*A(x)^4 + x^2*A(x).

1, 1, 5, 27, 177, 1270, 9645, 76206, 619913, 5156959, 43667985, 375140383, 3261467573, 28641957520, 253702185717, 2263964868768, 20334261430769, 183680693283325, 1667613040080061, 15208587941854251, 139266058402655669, 1279953660931370623

Offset: 0

Author

Seiichi Manyama, Nov 03 2023

Keywords

• nonn

Crossrefs

Cf. A365178, A365180, A365181, A365182, A365183, A367041, A367049, A367050.

Programs

PARI

a(n) = sum(k=0, n\2, binomial(3*n-5*k+1, k)*binomial(4*n-7*k, n-2*k)/(3*n-5*k+1));

Formula

a(n) = Sum_{k=0..floor(n/2)} binomial(3*n-5*k+1,k) * binomial(4*n-7*k,n-2*k)/(3*n-5*k+1).