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 A091697 #11 Jul 18 2025 07:38:48 %S A091697 2,3,5,9,17,33,35,65,129,257,513,1025,2049,4097,8193,16385,32769, %T A091697 65537,131073,262145,524289,1048577 %N A091697 Values of m corresponding to members of A088966. %C A091697 For every k >= 0, 2^k + 1 is in the sequence. %H A091697 Christian Hercher, <a href="https://arxiv.org/abs/2506.01099">On one of Erdős' Problems - An Efficient Search for Benelux Pairs</a>, arXiv:2506.01099 [math.NT], 2025. See pp. 2, 13. %e A091697 a(2) = 3, corresponding to A088966(2) = 8 because A007947(8) = A007947(3+1) and A007947(3) = A007947(8+1). %p A091697 rad:= n -> convert(numtheory:-factorset(n), `*`): %p A091697 count:= 0: lastr:= rad(1): %p A091697 for n from 2 to 10^7 do %p A091697 newr:= rad(n); %p A091697 P[lastr, newr]:= n-1; %p A091697 if assigned(P[newr, lastr]) then %p A091697 count:= count+1; A[count]:= n-1; M[count]:= P[newr, lastr]; %p A091697 fi; %p A091697 lastr:= newr; %p A091697 od: %p A091697 seq(M[n], n=1..count); # _Robert Israel_, Aug 11 2014 %K A091697 more,nonn,less %O A091697 1,1 %A A091697 _David Wasserman_, Jan 29 2004 %E A091697 a(13) from _Robert Israel_, Aug 11 2014 %E A091697 a(14)-a(22) from Hercher's paper by _Martin Fuller_, Jul 18 2025