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 A309276 #12 Sep 16 2019 04:44:57 %S A309276 1,5,3,2,10,15,7,4,6,9,11,22,13,35,21,8,17,45,19,25,14,33,23,12,20,65, %T A309276 27,18,29,75,31,16,24,51,85,30,37,95,39,26,41,105,43,55,50,69,47,40, %U A309276 28,49,125,34,53,135,99,44,38,57,59,118,61,155,63,32,52,143,67,134,46,115,71 %N A309276 a(n) is the smallest divisor not yet in the sequence of 5*T(n)= 5*n(n-1)/2, where T(n) are the triangular numbers; n => 1. %C A309276 Up to n = 10000, 1145 of the first 1228 odd primes appear as fixed points of a(n). %H A309276 Enrique Navarrete and Daniel Orellana, <a href="http://arxiv.org/abs/1907.10023">Finding Prime Numbers as Fixed Points of Sequences</a>, arXiv:1907.10023 [math.NT], 2019. %e A309276 For n = 1, 5*T(1) = 0, and a(1) = 1 is the smallest divisor of 0 not yet in the sequence. %e A309276 For n = 3, 5*T(3) = 15, and a(3) = 3 is a fixed point and the smallest divisor of 15 not yet in the sequence. %e A309276 For n = 71, 5*T(71) = 2485, and a(71) = 71 is a fixed point and the smallest divisor of 2485 not yet in the sequence. %Y A309276 Cf. A000217, A111273. %K A309276 nonn %O A309276 1,2 %A A309276 _Enrique Navarrete_, Jul 20 2019