A371932 G.f. A(x) satisfies A(x) = 1 + x/A(x)^2 * (1 + A(x)^5).

1, 2, 2, 26, 50, 706, 1650, 24282, 62370, 940610, 2554530, 39150810, 110311762, 1709993346, 4945525650, 77314273562, 228002115650, 3587763069826, 10741365151810, 169903043416730, 514833595840370, 8177978884039490, 25025386537586610

Offset

0,2

Links

Table of n, a(n) for n=0..22.

Formula

a(n) = (-1)^(n-1) * (1/n) * Sum_{k=0..n} binomial(n,k) * binomial(3*n-5*k-2,n-1) for n > 0.

a(n) == 2 (mod 8) for n > 0. - Hugo Pfoertner, Apr 13 2024

Prog

(PARI) a(n) = if(n==0, 1, (-1)^(n-1)*sum(k=0, n, binomial(n, k)*binomial(3*n-5*k-2, n-1))/n);

Crossrefs

Cf. A364393, A364394, A364396, A364397, A366364, A371893.

Cf. A349312, A366268, A371562, A371341.

Sequence in context: A120979 A348587 A032000 * A371639 A094347 A236286

Adjacent sequences: A371928 A371929 A371930 * A371934 A371935 A371936

Keyword

nonn

Author

Seiichi Manyama, Apr 13 2024

Status

approved