A368787 a(n) = (n+1) * (n!)^2 * Sum_{k=1..n} 1/((k+1) * (k!)^2).

0, 1, 7, 85, 1701, 51031, 2143303, 120024969, 8641797769, 777761799211, 85553797913211, 11293101324543853, 1761723806628841069, 320633732806449074559, 67333083889354305657391, 16159940133445033357773841, 4395503716297049073314484753

Offset

0,3

Links

Table of n, a(n) for n=0..16.

Formula

a(0) = 0; a(n) = (n+1) * n * a(n-1) + 1.

a(n) = A228229(n) - (n+1) * (n!)^2.

Prog

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

Crossrefs

Cf. A010790, A066998, A228229.

Sequence in context: A121020 A060237 A000424 * A207214 A000686 A102923

Adjacent sequences: A368784 A368785 A368786 * A368788 A368789 A368790

Keyword

nonn

Author

Seiichi Manyama, Jan 05 2024

Status

approved