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 A361461 #17 Mar 14 2023 18:31:47 %S A361461 2,5,7,8,11,13,15,17,19,20,23,26,27,29,31,34,35,37,39,41,43,44,47,48, %T A361461 49,53,54,55,56,59,61,62,63,65,67,69,71,73,74,75,76,79,80,83,84,87,89, %U A361461 92,94,95,97,98,99,101,103,104,107,109,110,111,113,116,118,119,120,123,124,125,127,129,131,132 %N A361461 Numbers k such that x(k+1) = 2 * x(k), when x(1)=1 and x(n) = x(n-1) + lcm(x(n-1),n), i.e., x(n) = A135504(n). %C A361461 Numbers k such that A135504(k) is a multiple of k+1. %C A361461 It is conjectured that this sequence gives also all numbers k for which A135506(k) is not a prime. See Ruiz-Cabello paper. %H A361461 Serafín Ruiz-Cabello, <a href="http://arxiv.org/abs/1504.05041">On the use of the lowest common multiple to build a prime-generating recurrence</a>, arXiv:1504.05041 [math.CO], 2015. %o A361461 (PARI) isA361461(n) = A361460(n); %Y A361461 Positions of 1's in A135506. %Y A361461 Cf. A135504, A361460 (characteristic function), A361464. %K A361461 nonn %O A361461 1,1 %A A361461 _Antti Karttunen_, Mar 13 2023