A370695 G.f. A(x) satisfies A(x) = (1 + x*A(x)^(3/4) / (1-x))^4.

1, 4, 22, 128, 777, 4872, 31330, 205560, 1370868, 9266104, 63343006, 437183260, 3042337215, 21323543252, 150395596016, 1066637271424, 7602188660799, 54422262148632, 391146728466980, 2821396586367568, 20417766975784066, 148200184917042112

Offset

0,2

Links

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

Formula

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

G.f.: A(x) = B(x)^4 where B(x) is the g.f. of A307678.

a(n) ~ 9 * 31^(n + 1/2) / (sqrt(Pi) * n^(3/2) * 2^(2*n + 3)). - Vaclav Kotesovec, Mar 29 2024

Prog

(PARI) a(n) = 4*sum(k=0, n, binomial(n-1, n-k)*binomial(3*k+4, k)/(3*k+4));

Crossrefs

Cf. A045902, A062109, A371379, A371486, A371517.

Cf. A270386, A307678, A371516.

Sequence in context: A047039 A100525 A199033 * A086682 A261399 A155862

Adjacent sequences: A370692 A370693 A370694 * A370696 A370697 A370698

Keyword

nonn

Author

Seiichi Manyama, Mar 27 2024

Status

approved