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 A378441 #9 Nov 26 2024 15:21:42
%S A378441 1,2,3,4,5,7,8,11,13,16,17,19,23,27,29,31,32,37,41,43,47,53,59,61,64,
%T A378441 67,71,73,79,83,89,97,101,103,107,109,113,125,127,128,131,137,139,149,
%U A378441 151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,243,251,256,257,263,269,271,277,281
%N A378441 Fixed points of A378226, where A278226 is XOR-Moebius transform of A318457, and A318457(n) = n XOR (sigma(n)-n).
%H A378441 Antti Karttunen, <a href="/A378441/b378441.txt">Table of n, a(n) for n = 1..20000</a>
%H A378441 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A378441 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A378441 {k such that A378226(k) is equal to k}.
%o A378441 (PARI)
%o A378441 A318457(n) = bitxor(n,sigma(n)-n);
%o A378441 A378226(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A318457(d)))); (v); }
%o A378441 isA378441(n) = (A378226(n)==n);
%Y A378441 Cf. A000040 (subsequence), A001065, A003987, A318457, A378226.
%K A378441 nonn
%O A378441 1,2
%A A378441 _Antti Karttunen_, Nov 26 2024