This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A193477 #6 Jul 30 2011 10:42:16 %S A193477 1,1,1,1,2,2,9,9,288,32,400,400,43200,43200,1058400,70560,18063360, %T A193477 18063360,6584094720,6584094720,3292047360000,156764160000, %U A193477 9484231680000,9484231680000,8194376171520000,327775046860800,27696991459737600,1025814498508800 %N A193477 Denominator(n!/floor(n/2)!^4). %F A193477 a(n) = Denominator(A056040(n)^2/n!). %F A193477 a(n) = Denominator(A056040(n)/floor(n/2)!^2). %p A193477 A193477 := n -> denom(n!/iquo(n,2)!^4); %Y A193477 Cf. A055773. %K A193477 nonn %O A193477 0,5 %A A193477 Peter Luschny, Jul 30 2011