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 A347875 #9 Sep 21 2021 21:31:40
%S A347875 1,6,21,28,496,8128
%N A347875 Numbers k such that A323905(sigma(k)) is equal to A323905(2*k).
%C A347875 Numbers k such that A323905(sigma(k)) = A332221(k) - A331750(k) is equal to 2*A156552(k) - A048675(k) = A156552(k) + A323905(k).
%H A347875 <a href="/index/O#opnseqs">Index entries for sequences where odd perfect numbers must occur, if they exist at all</a>
%o A347875 (PARI)
%o A347875 A048675(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; }; \\ From A048675
%o A347875 A156552(n) = {my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
%o A347875 A323905(n) = (A156552(n) - A048675(n));
%o A347875 isA347875(n) = (A323905(sigma(n))==A323905(2*n));
%Y A347875 Cf. A000203, A048675, A156552, A323905, A347876.
%Y A347875 Cf. also A000396 (subsequence), A331751, A347392.
%K A347875 nonn,more
%O A347875 1,2
%A A347875 _Antti Karttunen_, Sep 19 2021