A371543 G.f. A(x) satisfies A(x) = (1 + x*A(x) / (1+x))^4.

1, 4, 18, 100, 611, 3964, 26796, 186664, 1330541, 9657748, 71138964, 530417668, 3995461515, 30359913132, 232434013174, 1791205897652, 13883372595753, 108159238126644, 846472588860134, 6651825146945508, 52465622957295300, 415208597109815172

Offset: 0

Author

Seiichi Manyama, Mar 26 2024

Keywords

• nonn

Crossrefs

Cf. A371517.

Programs

PARI

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

Formula

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