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 A145612 #8 Mar 17 2019 02:04:36
%S A145612 1,6,15,420,63,1386,9009,360360,1531530,29099070,14549535,1338557220,
%T A145612 1673196525,10039179150,145568097675,72201776446800,18050444111700,
%U A145612 9025222055850,166966608033225,667866432132900,6845630929362225
%N A145612 Denominator of the polynomial A_l(x) = Sum_{d=1..l-1} x^(l-d)/d for index l=2n+1 evaluated at x=2.
%C A145612 For numerators see A145611. For general properties of A_l(x) see A145609.
%p A145612 A := proc(l,x) add(x^(l-d)/d,d=1..l-1) ; end: A145612 := proc(n) denom( A(2*n+1,2)) ; end: seq(A145612(n),n=1..20) ; # _R. J. Mathar_, Aug 21 2009
%t A145612 m = 2; aa = {}; Do[k = 0; Do[k = k + m^(2 r + 1 - d)/d, {d, 1, 2 r}]; AppendTo[aa, Denominator[k]], {r, 1, 30}]; aa (* _Artur Jasinski_ *)
%Y A145612 Cf. A145609 - A145640.
%K A145612 frac,nonn
%O A145612 1,2
%A A145612 _Artur Jasinski_, Oct 14 2008
%E A145612 Edited by _R. J. Mathar_, Aug 21 2009