A132911 a(n) = (n+1)*(2*n)!/2^n.
1, 2, 18, 360, 12600, 680400, 52390800, 5448643200, 735566832000, 125046361440000, 26134689540960000, 6585941764321920000, 1969196587532254080000, 689218805636288928000000, 279133616282697015840000000, 129517997955171415349760000000, 68255984922375335889323520000000
Offset: 0
Links
- Daniele Marchei, Emanuela Merelli, and Andrew Francis, Factorizing the Brauer monoid in polynomial time, arXiv:2402.07874 [math.RA], 2024. See p. 24.
Programs
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Mathematica
Table[(n+1) (2n)!/2^n,{n,0,20}] (* Harvey P. Dale, Jun 02 2020 *)
Formula
E.g.f.: 1/(1-x^2+x^4/4) (with interpolated zeros);
a(n)-(n+1)*(2*n-1)*a(n-1)=0. - R. J. Mathar, Nov 05 2012
Comments