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 A216767 #19 May 05 2022 08:06:26
%S A216767 5,45,90,1530,9945,278460,3063060,113333220,566666100,566666100,
%T A216767 23233310100,2346564320100,143140423526100,15904491502900,
%U A216767 2051679403874100,59498702712348900,59498702712348900,11721244434332733300,363358577464314732300
%N A216767 Denominators of partial sums of 1/A216765(n).
%C A216767 A216766 is the numerators of the partial sums of 1/A216765(n).
%H A216767 Amiram Eldar, <a href="/A216767/b216767.txt">Table of n, a(n) for n = 1..420</a>
%F A216767 a(n) = denominator(Sum_{k=1..n} 1/A216765(k)).
%e A216767 The partial sums are of the sequence of fractions: 1/5 + 1/9 + 1/10 + 1/17 + 1/26 + 1/28 + 1/33 + 1/37 + 1/50, ... and thus the partial sums are 1/5, 14/45, 37/90, 719/1530, 5056/9995, 151513/278460, 1759463/3063060, 68163191/113333220, 352149277/566666100, 360867217/566666100, 15078888947/23233310100, ...
%t A216767 Denominator[FoldList[Plus, 1/(1 + Select[Range[250], GCD @@ FactorInteger[#][[;; , 2]] > 1 &])]] (* _Amiram Eldar_, May 05 2022 *)
%Y A216767 Cf. A001597, A045542, A175064, A214390, A214391, A216765, A216766 (numerators).
%K A216767 nonn,easy,frac
%O A216767 1,1
%A A216767 _Jonathan Vos Post_, Sep 16 2012