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 A162447 #4 Jul 22 2025 06:55:22 %S A162447 12,720,181440,7257600,399168000,1307674368000,73229764608000, %T A162447 731699852083200,229909239772692480000,84300054583320576000000, %U A162447 51186993142992253747200000,21777738900836704321536000000 %N A162447 Denominators of the column sums of the ZG1 matrix. %C A162447 For the definition of the ZG1 matrix coefficients see A162446. %C A162447 We define the columns sums by cs(n) = sum(ZG1[2*m-1,n], m = 1.. infinity) for n => 2. %F A162447 a(n) = denom(cs(n)) and numer(cs(n)) = A162446(n). %Y A162447 See A162446 for the numerators of the column sums. %K A162447 easy,frac,nonn %O A162447 2,1 %A A162447 _Johannes W. Meijer_, Jul 06 2009