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 A236769 #18 Jan 04 2024 15:39:51
%S A236769 55,77,161,169,221,275,299,323,377,385,391,437,481,493,539,551,559,
%T A236769 605,611,629,689,697,703,715,731,779,793,799,817,847,893,901,923,935,
%U A236769 949,1001,1007,1027,1045,1073,1079,1121,1127,1147,1159,1241,1265,1271,1273,1309
%N A236769 Numbers n such that lpf(2^n -1) < lpf(2^lpf(n) -1).
%C A236769 The numbers n for which A049479(n) < A049479(lpf(n)), where lpf(n) = A020639(n). All other n satisfy the equality (in particular all primes).
%C A236769 All terms are odd and composite. - _Chai Wah Wu_, Oct 04 2019
%H A236769 Chai Wah Wu, <a href="/A236769/b236769.txt">Table of n, a(n) for n = 1..111</a>
%o A236769 (PARI) lpf(n) = vecmin(factor(n)[, 1]);
%o A236769 lista() = {my(vlpfmp = readvec("A049479.log")); for (i=2, #vlpfmp, if (vlpfmp[i] < vlpfmp[lpf(i)], print1(i, ", ")););} \\ _Michel Marcus_, Jan 31 2014
%Y A236769 Cf. A049479 (a question in the third comment).
%K A236769 nonn
%O A236769 1,1
%A A236769 _Thomas Ordowski_, Jan 31 2014
%E A236769 More terms from _Michel Marcus_, Jan 31 2014
%E A236769 More terms from _Chai Wah Wu_, Oct 04 2019