A134176 a(n) = (3/8)*(n-1)*(n-2)*(27*n^2-137*n+180).

0, 0, 9, 144, 765, 2475, 6120, 12789, 23814, 40770, 65475, 99990, 146619, 207909, 286650, 385875, 508860, 659124, 840429, 1056780, 1312425, 1611855, 1959804, 2361249, 2821410, 3345750, 3939975, 4610034, 5362119, 6202665, 7138350, 8176095, 9323064, 10586664

Offset

1,3

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 (5,-10,10,-5,1).

Formula

O.g.f.: 9*x^3*(1+11*x+15*x^2)/(1-x)^5 . - R. J. Mathar, Feb 01 2008

Mathematica

Table[(3/8)(n-1)(n-2)(27n^2-137n+180), {n, 40}]  (* Harvey P. Dale, Mar 23 2011 *)
LinearRecurrence[{5, -10, 10, -5, 1}, {0, 0, 9, 144, 765} , 50] (* G. C. Greubel, May 30 2016 *)

Prog

(PARI) a(n)=3*(n-1)*(n-2)*(27*n^2-137*n+180)/8 \\ Charles R Greathouse IV, Oct 21 2022

Crossrefs

Sequence in context: A050787 A017198 A281789 * A325173 A067415 A069134

Adjacent sequences: A134173 A134174 A134175 * A134177 A134178 A134179

Keyword

nonn,easy

Author

N. J. A. Sloane, Jan 30 2008

Status

approved