The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A246050 Number of endofunctions on [2n] where the smallest cycle length equals n. 4
 1, 3, 51, 4360, 861420, 302472576, 165549605760, 130241382036480, 139296260790086400, 194427690066299289600, 343266609438110040883200, 747889929370001008617062400, 1971026055567996899374212710400, 6180432763819774878006029844480000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..190 FORMULA a(n) = A246049(2n,n) = A243098(2n,n). a(n) ~ 2^(3*n-1/2) * n^(2*n-1) / exp(n). - Vaclav Kotesovec, Aug 19 2014 MAPLE with(combinat): b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i>n, 0, add((i-1)!^j*multinomial(n, n-i*j, i\$j)/j!* b(n-i*j, i+1), j=0..n/i))) end: A:= (n, k)-> add(binomial(n-1, j-1)*n^(n-j)*b(j, k), j=0..n): a:= n-> `if`(n=0, 1, A(2*n, n) -A(2*n, n+1)): seq(a(n), n=0..15); MATHEMATICA multinomial[n_, k_List] := n!/Times @@ (k!); b[n_, i_] := b[n, i] = If[n == 0, 1, If[i>n, 0, Sum[(i-1)!^j*multinomial[n, Join[{n-i*j}, Array[i&, j]]]/j!*b[n-i*j, i+1], {j, 0, n/i}]]]; A[n_, k_] := Sum[Binomial[n-1, j-1]*n^(n-j)*b[j, k], {j, 0, n}]; a[n_] := If[n == 0, 1, A[2*n, n] - A[2*n, n+1]]; Table[a[n], {n, 0, 15}] (* Jean-François Alcover, Feb 11 2015, after Alois P. Heinz *) CROSSREFS Cf. A241982, A246049, A243098. Sequence in context: A069343 A084882 A275798 * A091502 A307022 A330302 Adjacent sequences: A246047 A246048 A246049 * A246051 A246052 A246053 KEYWORD nonn AUTHOR Alois P. Heinz, Aug 11 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 24 12:09 EDT 2024. Contains 372773 sequences. (Running on oeis4.)