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 A332446 #15 Dec 13 2023 08:32:01 %S A332446 3,6,11,19,28,43,59,67,83,107,131,139,163,179,211,216,227,251,267,283, %T A332446 286,307,331,347,379,419,443,467,491,496,499,523,547,563,571,587,598, %U A332446 619,643,659,683,691,726,739,787,811,827,859,883,907,947,971,1019,1051,1091,1123,1163,1171,1187,1259,1283,1291,1307,1427,1451 %N A332446 Numbers k for which A087808(sigma(k)) is equal to A087808(2*k). %C A332446 Conjecture: includes all terms of A007520. - _Bill McEachen_, Dec 10 2023 %H A332446 Antti Karttunen, <a href="/A332446/b332446.txt">Table of n, a(n) for n = 1..20751</a> %H A332446 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %H A332446 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %o A332446 (PARI) %o A332446 A087808(n) = if(n<1, 0, if(n%2==0, 2*A087808(n/2), A087808((n-1)/2)+1)); %o A332446 isA332446(n) = (A087808(2*n)==A087808(sigma(n))); %Y A332446 Cf. A000203, A007520, A087808. %Y A332446 Subsequences: A000396, A332445. %Y A332446 Cf. A331751, A331752, A332208 for similar sequences. %K A332446 nonn %O A332446 1,1 %A A332446 _Antti Karttunen_, Feb 14 2020