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 A375524 #21 Jul 09 2025 05:05:20
%S A375524 1,2,6,12,60,20,140,280,2520,27720,27720,360360,360360,360360,720720,
%T A375524 12252240,4084080,77597520,77597520,77597520,1784742960,1784742960,
%U A375524 8923714800,8923714800,80313433200,11473347600,332727080400,332727080400,10314539492400,937685408400,937685408400
%N A375524 a(n) = denominator of Sum_{i=1..n} 1/A171397(i).
%H A375524 Alois P. Heinz, <a href="/A375524/b375524.txt">Table of n, a(n) for n = 1..2082</a>
%e A375524 The first few sums are 1, 3/2, 11/6, 25/12, 137/60, 49/20, 363/140, 761/280, 7129/2520, 80939/27720, 83249/27720, 1109957/360360, 1135697/360360, 1159721/360360, 2364487/720720, ...
%p A375524 b:= n-> (l-> add(l[i]*11^(i-1), i=1..nops(l)))(convert(n,base,10)):
%p A375524 g:= proc(n) option remember; `if`(n<1, 0, g(n-1)+1/b(n)) end:
%p A375524 a:= n-> denom(g(n)):
%p A375524 seq(a(n), n=1..31); # _Alois P. Heinz_, Aug 30 2024
%Y A375524 Cf. A171397, A375805, A375523, A001008/A002805.
%K A375524 nonn,frac
%O A375524 1,2
%A A375524 _N. J. A. Sloane_, Aug 30 2024