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 A324723 #6 Mar 15 2019 21:56:28
%S A324723 4,8,9,16,27,30,32,45,64,72,125,128,135,144,243,250,256,270,315,405,
%T A324723 420,480,490,512,576,600,675,756,810,825,875,988,1000,1024,1152,1155,
%U A324723 1210,1215,1458,1470,1600,1690,1716,1728,1920,2048,2100,2187,2250,2430,2450,2475,3125,3234,3240,3600,3645,3825,4320,4375,5070,5103
%N A324723 Numbers n such that bitor(2*k, sigma(k)) == 2k, where k = A156552(n).
%H A324723 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A324723 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A324723 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%o A324723 (PARI)
%o A324723 A156552(n) = {my(f = factor(n), 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 by _David A. Corneth_
%o A324723 isA324726(n) = ((2*n)==bitor(2*n, sigma(n)));
%o A324723 isA324723(n) = if(n>1,isA324726(A156552(n)));
%o A324723 (PARI) isA324723(n) = if(1==n,0,my(t=2*A156552(n)); (t==bitor(t,A323243(n)))); \\ Using also code from A323243.
%Y A324723 Cf. A156552, A323243, A324722, A324726.
%K A324723 nonn
%O A324723 1,1
%A A324723 _Antti Karttunen_, Mar 15 2019