A368776 a(n) = (n+1)^2 * (n!)^3 * Sum_{k=0..n} 1/((k+1)^2 * (k!)^3).

1, 5, 91, 4369, 436901, 78642181, 23120801215, 10358118944321, 6712061075920009, 6040854968328008101, 7309434511676889802211, 11578144266496193446702225, 23480476572454280309912112301, 59828254306613506229656062142949

Offset: 0

Author

Seiichi Manyama, Jan 05 2024

Keywords

• nonn

Crossrefs

Cf. A217284, A368775.

Cf. A368770.

Programs

PARI

a(n) = (n+1)^2*n!^3*sum(k=0, n, 1/((k+1)^2*k!^3));

Formula

a(n) = (n+1)^2 * n * a(n-1) + 1.