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 A363875 #15 Jul 21 2023 15:29:21 %S A363875 2,28,52,88,96,120,124,146,162,188,206,208,210,216,238,246,248,250, %T A363875 262,268,276,288,290,292,298,304,306,322,324,326,336,342,362,372,388, %U A363875 396,406,408,412,426,428,430,438,448,452,472,474,478,486,494,498,508,516 %N A363875 Numbers k such that there is no odd number whose aliquot sequence contains k. %C A363875 k is in sequence iff k can never be reached when iterating the map x -> A001065(x) starting with any odd number m. %C A363875 Assuming the stronger version of Goldbach conjecture, iff k is in the sequence, there are infinitely many odd numbers whose aliquot sequence contain k. %C A363875 Supersequence of A005114 (except 5), A283152, A284147, A284156, A284187, ..., and untouchable perfect numbers (28, 137438691328, ...), untouchable amicable numbers (A238382), untouchable sociable numbers. %H A363875 Andrew R. Booker, <a href="https://arxiv.org/abs/1610.07471">Finite connected components of the aliquot graph</a>, arXiv:1610.07471 [math.NT], 2017. %H A363875 Jean-Luc Garambois, <a href="http://www.aliquotes.com/graphinfinisuali.htm">Le graphe infini des suites aliquotes</a> (in French). %H A363875 Wikipedia, <a href="https://en.wikipedia.org/wiki/Aliquot_sequence">Aliquot sequence</a> %Y A363875 Cf. A001065, A005114, A238382, A283152, A284147, A284156, A284187. %K A363875 nonn %O A363875 1,1 %A A363875 _Jinyuan Wang_, Jun 25 2023