A034861 a(n) = n!*(3*n^2 - 15*n + 10)/6.

-8, 200, 3360, 43680, 551040, 7136640, 96768000, 1383782400, 20916403200, 334183449600, 5637529497600, 100255034880000, 1876076826624000, 36872930045952000, 759748346413056000, 16381540188389376000, 368990137906790400000, 8668429855133368320000

Offset

4,1

Links

G. C. Greubel, Table of n, a(n) for n = 4..445

J. Riordan, Enumeration of trees by height and diameter, IBM J. Res. Dev. 4 (1960), 473-478

Formula

(3*n^2-21*n+28)*a(n) - n*(3*n^2-15*n+10)*a(n-1) = 0. - R. J. Mathar, Apr 03 2017

E.g.f.: x^4*(1 -8*x +4*x^2)/(3*(-1+x)^3). - G. C. Greubel, Feb 22 2018

Mathematica

Table[n!*(3*n^2 -15*n +10)/6, {n, 4, 30}] (* G. C. Greubel, Feb 22 2018 *)

Prog

(PARI) for(n=4, 30, print1(n!*(3*n^2 -15*n +10)/6, ", ")) \\ G. C. Greubel, Feb 22 2018
(Magma) [Factorial(n)*(3*n^2 -15*n +10)/6: n in [4..30]]; // G. C. Greubel, Feb 22 2018

Crossrefs

Sequence in context: A232518 A229265 A323562 * A221121 A264124 A317631

Adjacent sequences: A034858 A034859 A034860 * A034862 A034863 A034864

Keyword

sign

Author

N. J. A. Sloane

Extensions

More terms from G. C. Greubel, Feb 22 2018

Status

approved