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 A326131 #35 Jan 03 2021 02:54:58
%S A326131 6,28,110,496,884,8128,18632,85936,116624,15370304,33550336,73995392,
%T A326131 815634435,3915380170,5556840416,6800695312,8589869056
%N A326131 Positive numbers n for which A000120(n) = k*A294898(n), with k < 0; numbers for which A326130(n) = sigma(n) - A005187(n).
%C A326131 No further terms below 2^31.
%C A326131 See also comments in A326133.
%C A326131 The quotients A000120(k)/(sigma(k)-A005187(k)) for these terms are: 1, 1, 5, 1, 3, 1, 5, 9, 2, 2, 1, 2, 2. Ones occur at the positions of perfect numbers.
%C A326131 a(18) > 10^11. - _Amiram Eldar_, Jan 03 2021
%H A326131 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A326131 <a href="/index/O#opnseqs">Index entries for sequences where any odd perfect numbers must occur</a>
%H A326131 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%e A326131 110 is "1101110" in binary, thus A000120(110) = 5. Sigma(110) = 216, while A005187(110) = 215, thus as 5 = 5*(216-215), 110 is included in this sequence.
%t A326131 q[n_] := Module[{bw = DigitCount[n, 2, 1], ab = DivisorSigma[1, n] - 2*n, sum}, (sum = ab + bw) > 0 && Divisible[bw, sum]]; Select[Range[10^5], q] (* _Amiram Eldar_, Jan 03 2021 *)
%o A326131 (PARI)
%o A326131 A005187(n) = { my(s=n); while(n>>=1, s+=n); s; };
%o A326131 isA326131(n) = { my(t=sigma(n)-A005187(n)); (gcd(hammingweight(n), t) == t); };
%Y A326131 Intersection of A326132 and A326133, also of A326132 and A326138.
%Y A326131 Cf. A000120, A000396 (subsequence), A005187, A294898, A295296, A295297, A295298, A295299, A326130.
%Y A326131 Cf. also A325981, A326141.
%K A326131 nonn,more
%O A326131 1,1
%A A326131 _Antti Karttunen_, Jun 09 2019
%E A326131 a(14)-a(17) from _Amiram Eldar_, Jan 03 2021