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 A336461 #7 Jul 24 2020 10:58:21
%S A336461 1,2,3,6,20,28,40,56,60,84,120,135,160,168,176,189,224,270,304,378,
%T A336461 480,496,528,585,672,819,912,1170,1372,1488,1638,1836,2156,2744,3025,
%U A336461 3672,3724,3780,4116,4312,4572,6050,6076,6468,6525,7448,7560,7956,8128,8232,9075,9144,9225,9261,10224,10880,10976,11172,12152,12936,13050,14144
%N A336461 Numbers k for which A335915(k) = A335915(sigma(k)).
%C A336461 Numbers k such that A335915(k) = A336455(k).
%C A336461 If terms x and y are present and gcd(x,y) = 1, then x*y is present also. This follows because both A335915 and A336455 are multiplicative sequences.
%C A336461 See also comments in A336464.
%H A336461 <a href="/index/O#opnseqs">Index entries for sequences where odd perfect numbers must occur, if they exist at all</a>
%o A336461 (PARI)
%o A336461 A000265(n) = (n>>valuation(n,2));
%o A336461 A335915(n) = { my(f=factor(n)); prod(k=1,#f~,if(2==f[k,1],1,(A000265((f[k,1]^2)-1)^f[k,2]))); };
%o A336461 isA336461(n) = (A335915(n)==A335915(sigma(n)));
%Y A336461 Cf. A000203, A000265, A335915, A336455.
%Y A336461 Subsequences: A000396, A005820.
%Y A336461 Cf. also A336462, A336463, A336464.
%K A336461 nonn
%O A336461 1,2
%A A336461 _Antti Karttunen_, Jul 22 2020