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 A326145 #15 Jun 19 2019 18:16:02
%S A326145 6,28,496,936,1638,8128,33550336
%N A326145 Numbers n for which n - A007947(n) is equal to gcd(n - A007947(n), sigma(n) - A007947(n) - n).
%C A326145 Numbers n such that either A066503(n) and A326143(n) are both zero or A066503(n) is not zero and divides A326143(n).
%C A326145 Question: Are there any odd terms?
%C A326145 No other terms < 2^31.
%H A326145 <a href="/index/O#opnseqs">Index entries for sequences where any odd perfect numbers must occur</a>
%o A326145 (PARI)
%o A326145 A007947(n) = factorback(factorint(n)[, 1]);
%o A326145 isA326145(n) = { my(b=A007947(n), t=n-b, u = (sigma(n)-b)-n); (gcd(t,u)==t); };
%o A326145 \\ Or alternatively as:
%o A326145 isA326145(n) = { my(t=A326143(n), u=A066503(n)); ((!u && !t)||(u && !(t%u))); };
%Y A326145 Cf. A000203, A000396 (a subsequence), A007947, A066503, A228058, A326142, A326143, A326144.
%K A326145 nonn,more
%O A326145 1,1
%A A326145 _Antti Karttunen_, Jun 09 2019