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 A386672 #26 Aug 04 2025 19:04:19 %S A386672 46,94,946,1139,1680,3804,4200,29975,31143,48560,53428,63840,74178, %T A386672 121400,125280,135720,279300,483392,679952 %N A386672 Integers x such that there exist four integers 0<y<=z<=t<=w such that sigma(x)^5 = x^5 + y^5 + z^5 + t^5 + w^5. %C A386672 The numbers x, y, z, t and w form a sigma-quintic quintuple. %C A386672 Other terms of the sequence: 5446350, 20201728, 326481408. %H A386672 S. I. Dimitrov, <a href="https://arxiv.org/abs/2408.07387">Generalizations of amicable numbers</a>, arXiv:2408.07387 [math.NT], 2024. %H A386672 James Waldby, <a href="https://pat7.com/jp/s515-10007-t">A Table of Fifth Powers equal to a Fifth Power</a> %e A386672 (46, 19, 43, 47, 67) is such a quintuple because sigma(46)^5 = 72^5 = 46^5 + 19^5 + 43^5 + 47^5 + 67^5. %e A386672 Other examples: (94, 38, 86, 92, 134), (946, 418, 1012, 1034, 1474), (1139, 323, 731, 782, 799), (63840, 144480, 154560, 157920, 225120). %Y A386672 Cf. A000203, A003350, A063922, A386225. %K A386672 nonn,hard,more %O A386672 1,1 %A A386672 _S. I. Dimitrov_, Jul 28 2025 %E A386672 More terms from _Michel Marcus_, Jul 29 2025