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 A089512 #13 Mar 15 2018 04:22:04 %S A089512 1,2,1,18,6,360,90,12600,2520,680400,113400,52390800,7484400, %T A089512 5448643200,681080400,735566832000,81729648000,125046361440000, %U A089512 12504636144000,26134689540960000,2375880867360000,6585941764321920000 %N A089512 Denominators used in the computation of the column sequences of array A078739 ((2,2)-Stirling2). %C A089512 See A089511 for the column sequence computation of A078739. %F A089512 a(n) = lcm(seq(denominator(b(n, m)), m=1..n-1)), n>=2, where b(n, m) is defined like A089511(n, m) but without the factor D(n) and lcm stands for the least common multiple of a set of numbers. %F A089512 a(n) = (sqrt(2)*n!/(8*2^(n/2)))*((n^2+4n+2*sqrt(2)+3)-(n^2+4n-2*sqrt(2)+3)*(-1)^n) [offset 0]. - _Paul Barry_, Sep 04 2007 %K A089512 nonn,easy %O A089512 2,2 %A A089512 _Wolfdieter Lang_, Dec 01 2003