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 A351440 #12 Feb 12 2022 23:47:56
%S A351440 1,6,28,496,8128,30240,32760,240408,2178540,6828720,13042080,23569920,
%T A351440 33550336,42402048,45532800,142990848,1379454720
%N A351440 Numbers k for which A003958(sigma(k)) + A064989(sigma(k)) is equal to A003958(k) + A064989(k).
%H A351440 <a href="/index/O#opnseqs">Index entries for sequences where odd perfect numbers must occur, if they exist at all</a>
%H A351440 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%o A351440 (PARI)
%o A351440 A003958(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1]--); factorback(f); };
%o A351440 A064989(n) = { my(f = factor(n>>valuation(n,2))); for(i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f); };
%o A351440 isA351440(n) = { my(s=sigma(n)); ((A003958(s)+A064989(s)) == (A003958(n)+A064989(n))); };
%Y A351440 Cf. A000203, A003958, A064989, A351442.
%Y A351440 Subsequence of A351446.
%Y A351440 Subsequences: A000396, A336702.
%K A351440 nonn,more
%O A351440 1,2
%A A351440 _Antti Karttunen_, Feb 12 2022