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 A375229 #8 Aug 06 2024 11:14:27
%S A375229 1,4,8,9,12,18,20,24,25,27,28,36,40,44,45,49,50,52,54,56,60,63,68,72,
%T A375229 75,76,84,88,90,92,98,99,100,104,108,116,117,120,121,124,125,126,132,
%U A375229 135,136,140,147,148,150,152,153,156,164,168,169,171,172,175,180,184
%N A375229 Numbers k such that A299090(k) is even.
%C A375229 Differs from A252849 by having the terms 1, 256, 512, 768, 1280, ..., and not having the terms 64, 128, 144, 192, 288, ... .
%C A375229 Numbers whose maximum exponent in their unique factorization in terms of distinct "Fermi-Dirac primes" (A368781) is not a power of 4.
%C A375229 The asymptotic density of this sequence is Sum_{k>=1} (1/zeta(4^k) - 1/zeta(2^(2*k-1))) = 0.32005681814901480646... .
%H A375229 Amiram Eldar, <a href="/A375229/b375229.txt">Table of n, a(n) for n = 1..10000</a>
%t A375229 q[n_] := EvenQ[IntegerLength[Max[FactorInteger[n][[;; , 2]]], 2]]; q[1] = True; Select[Range[200], q]
%o A375229 (PARI) is(n) = if(n == 1, 1, !(#binary(vecmax(factor(n)[, 2])) % 2));
%Y A375229 Cf. A252849, A299090, A368781.
%K A375229 nonn,easy,base
%O A375229 1,2
%A A375229 _Amiram Eldar_, Aug 06 2024