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 A364289 #7 Jul 25 2023 12:31:05
%S A364289 3,5,6,7,10,11,12,13,14,17,19,20,21,22,23,24,26,28,29,31,33,34,37,38,
%T A364289 39,40,41,42,43,44,46,47,48,51,52,53,55,56,57,58,59,61,62,65,66,67,68,
%U A364289 69,71,73,74,76,78,79,80,82,83,84,85,86,87,88,89,91,92,93,94,95,96,97,99,101,102,103,104,106,107,109
%N A364289 Numbers k such that A243071(k) >= k.
%C A364289 If k is present, then 2*k is also present, and vice versa.
%o A364289 (PARI)
%o A364289 A064989(n) = { my(f=factor(n>>valuation(n,2))); for(i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f); };
%o A364289 A243071(n) = if(n<=2, n-1, if(!(n%2), 2*A243071(n/2), 1+(2*A243071(A064989(n)))));
%o A364289 isA364289(n) = (A243071(n)>=n);
%Y A364289 Positions of terms <= 0 in A364288.
%Y A364289 Cf. A007283 (subsequence), A243071, A364290 (complement).
%Y A364289 Cf. also A364287.
%K A364289 nonn
%O A364289 1,1
%A A364289 _Antti Karttunen_, Jul 25 2023