A371617 G.f. satisfies A(x) = ( 1 + x / (1 - x*A(x)^3)^3 )^2.

1, 2, 7, 54, 419, 3644, 33366, 317672, 3113559, 31200060, 318219653, 3292546660, 34475311605, 364621943538, 3889561661610, 41799988930926, 452126713579192, 4918321519144206, 53773399008883695, 590578523863692086, 6512515698908748358

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..934

Formula

a(n) = Sum_{k=0..n} binomial(6*(n-k)+2,k) * binomial(n+2*k-1,n-k)/(3*(n-k)+1).

Prog

(PARI) a(n, r=2, s=3, t=0, u=6) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(n+(s-1)*k-1, n-k)/(t*k+u*(n-k)+r));

Crossrefs

Cf. A371613, A371615.

Cf. A371616.

Sequence in context: A168558 A024027 A079410 * A283335 A326207 A280221

Adjacent sequences: A371614 A371615 A371616 * A371618 A371619 A371620

Keyword

nonn

Author

Seiichi Manyama, Mar 29 2024

Status

approved