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 A362805 #5 May 05 2023 01:41:58
%S A362805 1,6,28,30,45,496,8128,16380,57720,65472,235246,683520,33550336,
%T A362805 50426880,60945408,105553910,131297280,3052879872,8589869056
%N A362805 Primitive terms of A362804: terms k of A362804 such that k/2 is not a term of A362804.
%C A362805 If k is a term then k*2^m is a term of A362804 for all m >= 0.
%C A362805 The odd terms of A362804 and this sequence are common by definition. Are 1 and 45 the only odd terms?
%C A362805 All the even perfect numbers (A000396) are terms.
%C A362805 a(20) > 2*10^11, if it exists.
%t A362805 q[n_] := IntegerQ[HarmonicMean[Select[Divisors[n], BitAnd[n, #] == # &]]]; Select[Range[10^6], q[#] && (OddQ[#] || ! q[#/2]) &]
%o A362805 (PARI) div(n) = select(x->(bitor(x, n) == n), divisors(n));
%o A362805 is1(n) = {my(d = div(n)); denominator(#d/sum(i = 1, #d ,1/d[i])) == 1;}
%o A362805 is(n) = is1(n) && (n%2 || !is1(n/2));
%Y A362805 Subsequence of A362804.
%Y A362805 Cf. A000396.
%K A362805 nonn,base,more
%O A362805 1,2
%A A362805 _Amiram Eldar_, May 04 2023