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%I #17 Oct 31 2024 06:49:36
%S 1,1,140,168000,812011200,11021058048000,339782903171712000,
%T 20692894514095964160000,2254632317437500000000000000,
%U 408212019690599470111653888000000,115985264066835726820369478446080000000,49409573278650211500346024173376634880000000,30404587048380414443886075636144408738201600000000
%N a(n) = (3*n)!*((3*n+1)/6)^n/(3*n+1).
%H Thorsten Weist, <a href="http://arxiv.org/abs/1203.2740">On the Euler characteristic of Kronecker moduli spaces</a>, arXiv preprint arXiv:1203.2740 [math.RT], 2012. Cor. 5.3, k=3.
%t Table[(3 n)! ((3 n + 1) / 6)^n / (3 n + 1), {n, 0, 30}] (* _Vincenzo Librandi_, Dec 12 2014 *)
%o (Magma) [Factorial(3*n)*((3*n+1)/6)^n/(3*n+1): n in [0..20]]; // _Vincenzo Librandi_, Dec 12 2014
%K nonn,easy
%O 0,3
%A _N. J. A. Sloane_, Sep 16 2012