A216729 (3*n)!*((3*n+1)/6)^n/(3*n+1).

1, 1, 140, 168000, 812011200, 11021058048000, 339782903171712000, 20692894514095964160000, 2254632317437500000000000000, 408212019690599470111653888000000, 115985264066835726820369478446080000000, 49409573278650211500346024173376634880000000, 30404587048380414443886075636144408738201600000000

Offset

0,3

Links

Table of n, a(n) for n=0..12.

Thorsten Weist, On the Euler characteristic of Kronecker moduli spaces, arXiv preprint arXiv:1203.2740, 2012. Cor. 5.3, k=3.

Mathematica

Table[(3 n)! ((3 n + 1) / 6)^n / (3 n + 1), {n, 0, 30}] (* Vincenzo Librandi, Dec 12 2014

Prog

(Magma) [Factorial(3*n)*((3*n+1)/6)^n/(3*n+1): n in [0..20]]; // Vincenzo Librandi, Dec 12 2014

Crossrefs

Sequence in context: A181238 A211420 A185402 * A350614 A058939 A214376

Adjacent sequences: A216726 A216727 A216728 * A216730 A216731 A216732

Keyword

nonn

Author

N. J. A. Sloane, Sep 16 2012

Status

approved