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 A209201 A lower bound on the number of the distinct maximum genus embedding of the complete bipartite graph K(n,n). 0
 1, 0, 16, 0, 7739670528, 0, 137105941502361600000000000000, 0, 6990502336758588607110928994980286070521856000000000000000000, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Theorem A, p. 3, of Dong. LINKS Guanghua Dong, Han Ren, Ning Wang, Yuanqiu Huang, Lower bound on the number of the maximum genus embedding of K_{n,n}, arXiv:1203.0855 [math.CO] FORMULA For n odd, a(n) = 2^((n-1)/2)*(n-2)!!^n*(n-1)!^n; otherwise a(n) = 0. PROG (PARI) a(n)=if(n%2, 2^(n\2)*prod(i=1, n\2, 2*i-1)^n*(n-1)!^n, 0) \\ Charles R Greathouse IV, Jun 19 2013 CROSSREFS Cf. A000142 (factorial numbers), A001147 (double factorial numbers). Sequence in context: A173436 A081263 A265491 * A050467 A008835 A040259 Adjacent sequences:  A209198 A209199 A209200 * A209202 A209203 A209204 KEYWORD nonn,easy AUTHOR Jonathan Vos Post, Mar 06 2012 EXTENSIONS Terms corrected by Charles R Greathouse IV, Jun 19 2013 STATUS approved

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Last modified December 7 00:16 EST 2019. Contains 329812 sequences. (Running on oeis4.)