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 A319937 #8 Feb 16 2025 08:33:56 %S A319937 525150234,527787366,528544218,553128198,612951066,675192294, %T A319937 735821562,982674438,998151162,998151174,5251502340,5277873660, %U A319937 5285442180,5531281980,6129510660,6751922940,7358215620,9826744380,9981511620,9981511740 %N A319937 Unitary sociable numbers of order 10. %H A319937 J. O. M. Pedersen, <a href="http://web.archive.org/web/20130731050921/http://amicable.homepage.dk/knwnux.htm">Known Unitary Sociable Numbers of order different from four</a> [Via Internet Archive Wayback-Machine] %H A319937 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/UnitarySociableNumbers.html">Unitary Sociable Numbers</a> %H A319937 J. O. M. Pedersen, <a href="/A319937/a319937.txt">Order 10 cycles</a> %o A319937 (PARI) f(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)) - n; %o A319937 isok10(n) = iferr(f(f(f(f(f(f(f(f(f(f(n)))))))))) == n, E, 0); %o A319937 isok5(n) = iferr(f(f(f(f(f(n))))) == n, E, 0); %o A319937 isok2(n) = iferr(f(f(n)) == n, E, 0); %o A319937 isok1(n) = iferr(f(n) == n, E, 0); %o A319937 isok(n) = isok10(n) && !isok1(n) && !isok2(n) && !isok5(n); %Y A319937 Cf. A063919 (sum of proper unitary divisors). %Y A319937 Cf. A002827 (unitary perfect), A063991 (unitary amicable). %Y A319937 Cf. A097024 (order 5), A319917 (order 6), A097030 (order 14). %K A319937 nonn,more %O A319937 1,1 %A A319937 _Michel Marcus_, Oct 02 2018