OFFSET
1,2
LINKS
N. J. Calkin, B. Novick and H. Ushijima-Mwesigwa, What Moser Could Have Asked: Counting Hamilton Cycles in Tournaments, arXiv:1506.00699 [math.CO], 2015.
FORMULA
a(n) = Sum_{k=1..n} (S(n,k)*k!)^3/k, where S(n,k) is the Stirling number of the second kind (A048993, Stirling set numbers).
PROG
(PARI) a(n)=sum(k=1, n, (stirling(n, k, 2)*k!)^3/k) \\ Charles R Greathouse IV, Jun 03 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Hayato Ushijima-Mwesigwa, Jun 03 2015
EXTENSIONS
Offset changed to 1 by Georg Fischer, Jun 20 2022
STATUS
approved