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 A363461 #7 Jun 22 2023 05:59:29 %S A363461 2,208,388,298,838 %N A363461 Least n-untouchable number. %C A363461 Let s^m(k) denote the m-th iterate of s(k) = sigma(k) - k. n-untouchable numbers are the numbers that lie in the image of s^(n-1)(k), but not in the image of s^n(k). %H A363461 Kevin Chum, Richard K. Guy, Michael J. Jacobson Jr. and Anton S. Mosunov, <a href="https://arxiv.org/abs/2110.14136">Numerical and Statistical Analysis of Aliquot Sequences</a>, arXiv:2110.14136 [math.NT], 2021. %Y A363461 Cf. A005114, A152454, A283152, A284147, A284156, A284187. %K A363461 nonn,more %O A363461 1,1 %A A363461 _Jinyuan Wang_, Jun 03 2023