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 A112566 #9 Jun 23 2020 19:09:57
%S A112566 1,3,9,31,109,421,1585,5454,20681,80983,311221,1168531,4505761,
%T A112566 17907735,69240865,272109736,1078430833,4147985381,16383884581,
%U A112566 64335012378,234179431201,929947274509,3651532869601,14453209093051,56596999501225
%N A112566 a(n) = (A112565(n) - 1)/n for n>=1.
%C A112566 A112565 is the main diagonal of square table A112564 of generalized Flavius Josephus sieves.
%H A112566 <a href="/index/J#Josephus">Index entries for sequences related to the Josephus Problem</a>
%o A112566 (PARI) {a(n)=local(A=n,B=0,k=0);if(n<1,0, until(A==B,k=k+1;if(k%n==0,k=k+1);B=A;A=floor(A*(k+1)/k));A/n)}
%Y A112566 Cf. A112564, A112565, A112567.
%K A112566 nonn
%O A112566 1,2
%A A112566 _Paul D. Hanna_, Oct 14 2005
%E A112566 More terms from _David Wasserman_, Jun 30 2009