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

0,3

Links

Table of n, a(n) for n=0..21.

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).

Prog

(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));

Crossrefs

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

Sequence in context: A225309 A231091 A205774 * A326094 A232683 A240637

Adjacent sequences: A367045 A367046 A367047 * A367049 A367050 A367051

Keyword

nonn

Author

Seiichi Manyama, Nov 03 2023

Status

approved