A366980 G.f. satisfies A(x) = 1 + x*A(x)^5 * (1 - x*A(x)).

1, 1, 4, 24, 171, 1336, 11060, 95298, 845649, 7675398, 70921457, 664905445, 6309060313, 60473691666, 584684295383, 5695312881404, 55839455579659, 550621231581791, 5457218248143692, 54332533436452743, 543148496962279730, 5449742750024662824

Offset: 0

Author

Seiichi Manyama, Nov 01 2023

Keywords

• nonn

Crossrefs

Cf. A000108, A200754.

Cf. A365185, A367017.

Programs

PARI

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

Formula

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