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 A069083 #18 Sep 08 2022 08:45:05 %S A069083 8,40,72,104,136,200,232,296,328,360,384,392,424,488,520,584,648,680, %T A069083 712,776,808,872,904,936,968,1000,1096,1160,1192,1224,1256,1352,1384, %U A069083 1408,1448,1480,1544,1576,1640,1768,1832,1864,1920,1928,1960,2048,2056 %N A069083 Numbers n such that sigma(n)/tau(n) has denominator 4. %H A069083 Amiram Eldar, <a href="/A069083/b069083.txt">Table of n, a(n) for n = 1..10000</a> %F A069083 n such that A057021(n)=4. %t A069083 Select[Range[500], Denominator[DivisorSigma[1, #]/DivisorSigma[0, #]] == 4 &] (* _Amiram Eldar_, Sep 08 2019 *) %o A069083 (Magma) [n:n in [1..2100]|Denominator(SumOfDivisors(n)/#Divisors(n)) eq 4]; // _Marius A. Burtea_, Sep 08 2019 %Y A069083 Cf. A000005, A000203, A057021. %K A069083 easy,nonn %O A069083 1,1 %A A069083 _Benoit Cloitre_, Apr 05 2002