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 A355279 #10 Feb 16 2025 08:34:03
%S A355279 30240,32760,2178540,23569920,45532800,46475520,48933360,50995620,
%T A355279 60933600,69995520,72807696,142990848
%N A355279 Numbers k such that S(S(S(k))) = k, with S(n) = sigma(n)/4: 1/4-sociable numbers of order 1 or 3.
%C A355279 a(6..11) = { 46475520, 48933360, 50995620, ..., 72807696 } are the first terms not in A027687 (4-perfect numbers), which is obviously a subsequence.
%C A355279 a(11..12) = { 72807696, 142990848 } are the first terms that are not multiples of 60.
%H A355279 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SociableNumbers.html">Sociable Numbers</a>
%o A355279 (PARI) is_A355279(n, f(x)=if(x && x%4==0, sigma(x\4)))= f(f(sigma(n)))==n*4
%Y A355279 A027687 is a subsequence.
%Y A355279 Cf. A113286 (1/4 sociable numbers of order <= 2), A113546 (1/3-sociable numbers).
%K A355279 nonn,more
%O A355279 1,1
%A A355279 _M. F. Hasler_, Sep 25 2022