A134241 a(n) = 8*(n-1)*(n-2)*(n-3)*(6*n^2-37*n+60).

0, 0, 0, 384, 4800, 25920, 91200, 248640, 572544, 1169280, 2183040, 3801600, 6262080, 9856704, 14938560, 21927360, 31315200, 43672320, 59652864, 80000640, 105554880, 137256000, 176151360, 223401024, 280283520, 348201600, 428688000, 523411200

Offset

1,4

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

D. Zvonkine, Home Page

D. Zvonkine, Counting ramified coverings and intersection theory on Hurwitz spaces II (local structure of Hurwitz spaces and combinatorial results), Moscow Mathematical Journal, vol. 7 (2007), no. 1, 135-162.

Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).

Formula

O.g.f.: 192*x^4*(3*x+2)*(5*x+1)/(-1+x)^6 . - R. J. Mathar, Feb 01 2008

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6). - G. C. Greubel, May 30 2016

Mathematica

LinearRecurrence[{6, -15, 20, -15, 6, -1}, {0, 0, 0, 384, 4800, 25920}, 50] (* or *) Table[8 (n - 1) (n - 2) (n - 3) (6 n^2 - 37 n + 60), {n, 1, 25}] (* G. C. Greubel, May 30 2016 *)

Crossrefs

Sequence in context: A252904 A252899 A183686 * A203980 A061403 A281656

Adjacent sequences: A134238 A134239 A134240 * A134242 A134243 A134244

Keyword

nonn,easy

Author

N. J. A. Sloane, Jan 30 2008

Status

approved