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

%I

%S -8,200,3360,43680,551040,7136640,96768000,1383782400,20916403200,

%T 334183449600,5637529497600,100255034880000,1876076826624000,

%U 36872930045952000,759748346413056000,16381540188389376000,368990137906790400000,8668429855133368320000

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

%H G. C. Greubel, <a href="/A034861/b034861.txt">Table of n, a(n) for n = 4..445</a>

%H J. Riordan, <a href="http://dx.doi.org/10.1147/rd.45.0473">Enumeration of trees by height and diameter</a>, IBM J. Res. Dev. 4 (1960), 473-478

%F (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

%F E.g.f.: x^4*(1 -8*x +4*x^2)/(3*(-1+x)^3). - _G. C. Greubel_, Feb 22 2018

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

%o (PARI) for(n=4,30, print1(n!*(3*n^2 -15*n +10)/6, ", ")) \\ _G. C. Greubel_, Feb 22 2018

%o (MAGMA) [Factorial(n)*(3*n^2 -15*n +10)/6: n in [4..30]]; // _G. C. Greubel_, Feb 22 2018

%K sign

%O 4,1

%A _N. J. A. Sloane_

%E More terms from _G. C. Greubel_, Feb 22 2018

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Last modified December 1 09:39 EST 2021. Contains 349426 sequences. (Running on oeis4.)