A141009 E.g.f. exp(Sum_{d|M} (exp(d*x)-1)/d), M=13.

1, 2, 18, 262, 4498, 88174, 1989162, 51366438, 1491069602, 47749828830, 1664928894170, 62693869629142, 2534737217687378, 109469680507411214, 5025930552213949450, 244236790780300327302, 12515419830686362586882

Offset

0,2

Comments

Also the number of partitions of {1..(13n)} that are invariant under a permutation consisting of n 13-cycles. - Danny Rorabaugh, Oct 29 2015

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

T. S. Motzkin, Sorting numbers for cylinders and other classification numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, pp. 167-176. [Annotated, scanned copy]

OEIS Wiki, Sorting numbers

Mathematica

u[0, j_]: = 1; u[k_, j_]: = u[k, j] = Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 13], {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2012, after Wouter Meeussen in similar sequences *)
mx = 16; p = 13; Range[0, mx]! CoefficientList[ Series[ Exp[ (Exp[p*x] - p - 1)/p + Exp[x]], {x, 0, mx}], x] (* Robert G. Wilson v, Dec 12 2012 *)

Crossrefs

Column 13 of A162663.

Sequence in context: A360974 A350461 A099880 * A143154 A032037 A351276

Adjacent sequences: A141006 A141007 A141008 * A141010 A141011 A141012

Keyword

nonn

Author

R. J. Mathar, Jul 11 2008

Status

approved