cp's OEIS Frontend

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.

A098188 Irregular triangle with 4 columns which contains in each row the members of a 4-cycle under the map x->A063919(x), iteration of summing the proper-unitary divisors.

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%I A098188 #12 Feb 16 2025 08:32:54
%S A098188 263820,263940,280380,280500,395730,395910,420570,420750,172459210,
%T A098188 218725430,272130250,218628662,209524210,246667790,231439570,
%U A098188 230143790,384121920,384296640,408233280,408408000
%N A098188 Irregular triangle with 4 columns which contains in each row the members of a 4-cycle under the map x->A063919(x), iteration of summing the proper-unitary divisors.
%C A098188 Initial values attracted by this sequence are in A098187.
%C A098188 The iteration of this function also contains 2-cycles like 114->126->114... or 1140 -> 1260 ->1140,... or 3-cycles like 30->42->54->30->....
%H A098188 J. O. M. Pedersen, <a href="http://web.archive.org/web/20130731051700/http://amicable.homepage.dk/knwnu4.htm">Known Unitary Sociable Numbers of order four</a> [Via Internet Archive Wayback-Machine]
%H A098188 J. O. M. Pedersen, <a href="/A319902/a319902.txt">Order 4 cycles</a>, 2007.
%H A098188 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/UnitarySociableNumbers.html">Unitary Sociable Numbers</a>
%e A098188 The first line represents the 4-cycle  280500->263820->263940->280380->280500->...,
%e A098188 The second line represents the 4-cycle 420750->395730->395910->420570->420750->..
%Y A098188 Cf. A098185, A098186, A002827, A097024, A097030, A098187.
%Y A098188 Cf. A319902 (where the terms are entered by increasing value).
%K A098188 nonn,tabf,more
%O A098188 1,1
%A A098188 _Labos Elemer_, Sep 02 2004
%E A098188 More terms from _Michel Marcus_, Oct 05 2018