A349023 G.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^4)^2.

1, 2, 11, 64, 417, 2892, 20941, 156500, 1198049, 9346690, 74042938, 594001236, 4815995027, 39399831458, 324840184326, 2696343599336, 22514057175337, 188977375146888, 1593661234493561, 13495942411592260, 114723671513478118, 978570384358686064

Offset

0,2

Links

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

Formula

If g.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^s)^t, then a(n) = Sum_{k=0..n} binomial(t*n-(t-1)*(k-1),k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).

Prog

(PARI) a(n, s=4, t=2) = sum(k=0, n, binomial(t*n-(t-1)*(k-1), k)*binomial(n+(s-1)*k-1, n-k)/(n-k+1));

Crossrefs

Cf. A118971, A321798, A349024.

Sequence in context: A373890 A038725 A161947 * A001565 A357845 A199412

Adjacent sequences: A349020 A349021 A349022 * A349024 A349025 A349026

Keyword

nonn

Author

Seiichi Manyama, Nov 06 2021

Status

approved