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 A364976 #16 Sep 02 2023 02:38:58
%S A364976 180,240,360,420,540,600,780,1080,1344,1872,1890,2016,2184,2352,2376,
%T A364976 2688,3192,3276,3744,4284,4320,4680,5292,5376,5796,6048,6552,7128,
%U A364976 7440,8190,10416,13776,14850,18600,19824,19872,20496,21528,22932,25056,26208,26496,26784
%N A364976 3-abundant numbers k such that k/(sigma(k)-3*k) is an integer.
%C A364976 Analogous to A153501 as 3-abundant numbers (A068403) are analogous to abundant numbers (A005101).
%C A364976 Numbers k such that the sum of the divisors of k except for one of them is equal to 3*k.
%H A364976 Amiram Eldar, <a href="/A364976/b364976.txt">Table of n, a(n) for n = 1..576</a> (terms below 2.5*10^10)
%e A364976 180 is a term since sigma(180) - 3*180 = 6 > 0 and 180 is divisible by 6.
%t A364976 Select[Range[27000], (d = DivisorSigma[1, #] - 3*#) > 0 && Divisible[#, d] &]
%o A364976 (PARI) is(n) = {my(d = sigma(n) - 3*n); d > 0 && n%d == 0;}
%Y A364976 Subsequence of A068403.
%Y A364976 A027687 is a subsequence.
%Y A364976 Cf. A000203 (sigma), A005101, A005820, A055153, A153501, A160320, A218404, A218406, A329189, A364977.
%K A364976 nonn
%O A364976 1,1
%A A364976 _Amiram Eldar_, Aug 15 2023