A274294 a(n) = 1+(n+1)^2+n!+Sum_{k=1..n-1} binomial(n,k)*n!/(n-k)!.

3, 6, 16, 50, 234, 1582, 13376, 130986, 1441810, 17572214, 234662352, 3405357826, 53334454586, 896324308830, 16083557845504, 306827170866362, 6199668952527906, 132240988644216166, 2968971263911289360, 69974827707903049554, 1727194482044146637962

Offset

0,1

Comments

Number of residuated maps on the lattice M_n.

Links

Table of n, a(n) for n=0..20.

Erika D. Foreman, Order automorphisms on the lattice of residuated maps of some special nondistributive lattices, (2015). Univ. Louisville, Electronic Theses and Dissertations. Paper 2257.

Formula

a(n) = (n+1)^2 +n! + A070779(n-1), n>=1. - R. J. Mathar, Jul 16 2020

Maple

f:=n->1+(n+1)^2+n!+add(binomial(n, k)*n!/(n-k)!, k=1..n-1);
[seq(f(n), n=0..20)];

Mathematica

Table[1+(n+1)^2+n!+Sum[Binomial[n, k] n!/(n-k)!, {k, n-1}], {n, 0, 20}] (* Harvey P. Dale, Feb 17 2023 *)

Crossrefs

Cf. A317094.

Sequence in context: A369073 A300355 A360865 * A201969 A367639 A340498

Adjacent sequences: A274291 A274292 A274293 * A274295 A274296 A274297

Keyword

nonn

Author

N. J. A. Sloane, Jun 18 2016

Status

approved