OFFSET
4,1
REFERENCES
Lando S. K. and Zvonkine D., Counting ramified coverings and intersection theory on Hurwitz spaces I (cohomological identities). Moscow Mathematical Journal, vol. 7 (2007), no. 1, 85-107.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 4..211
D. Zvonkine, Home Page
MATHEMATICA
Table[3/(4(n-3)!) (27n^2-137n+180)(n^(n-6))(2n-6)!, {n, 4, 20}] (* Harvey P. Dale, Nov 01 2024 *)
PROG
(PARI) a(n)=(3/4)*(27*n^2-137*n+180)*n^(n-6)*(2*n-6)!/(n-3)! \\ Charles R Greathouse IV, May 01 2020
CROSSREFS
KEYWORD
nonn,easy,changed
AUTHOR
N. J. A. Sloane, Jan 30 2008
STATUS
approved