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 A322486 #13 Jul 17 2021 06:59:46
%S A322486 6,60,90,264,3960,4560,8736,13770,131040,384384,605880,5765760,
%T A322486 20049120,882161280,23253135360
%N A322486 Semi-unitary perfect numbers: numbers k such that susigma(k) = 2k, where susigma(k) is the sum of the semi-unitary divisors of k (A322485).
%C A322486 a(16) <= 1846273228800. - _David A. Corneth_, Dec 11 2018
%e A322486 264 is in the sequence since its sum of semi-unitary divisors is susigma(264) = 528 = 2 * 264.
%t A322486 f[p_, e_] := (p^Floor[(e+1)/2] - 1)/(p-1) + p^e; susigma[n_] := If[n==1, 1, Times @@ (f @@@ FactorInteger[n])]; aQ[n_] := susigma[n]==2n; Select[Range[10000], aQ]
%o A322486 (PARI) ssu(n) = {my(f = factor(n)); for (k=1, #f~, my(p=f[k,1], e=f[k,2]); f[k,1] = (p^((e+1)\2) - 1)/(p-1) + p^e; f[k,2] = 1;); factorback(f);} \\ A322485
%o A322486 isok(n) = ssu(n) == 2*n; \\ _Michel Marcus_, Dec 14 2018
%Y A322486 Cf. A000396, A002827, A322485.
%K A322486 nonn,more
%O A322486 1,1
%A A322486 _Amiram Eldar_, Dec 11 2018