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 A377844 #9 Nov 10 2024 05:03:59
%S A377844 8,24,27,32,40,54,56,72,88,96,104,108,120,125,128,135,136,152,160,168,
%T A377844 184,189,200,224,232,243,248,250,264,270,280,288,296,297,312,328,343,
%U A377844 344,351,352,360,375,376,378,384,392,408,416,424,432,440,456,459,472,480,486,488,500
%N A377844 Numbers that have a single odd exponent larger than 1 in their prime factorization.
%C A377844 First differs from A295661, A325990 and A376142 at n = 24: A295661(24) = A325990(24) = A376142(24) = 216 = 2^3 * 3^3 is not a term of this sequence.
%C A377844 Differs from A060476 by having the terms 432, 648, 1728, ..., and not having the terms 1, 216, 256, 768, 864, ... .
%C A377844 The asymptotic density of this sequence is Product_{p prime} (1 - 1/(p^2*(p+1))) * Sum_{p prime} (1/(p^3+p^2-1)) = 0.11498368544519741081... .
%H A377844 Amiram Eldar, <a href="/A377844/b377844.txt">Table of n, a(n) for n = 1..10000</a>
%t A377844 q[n_] := Count[FactorInteger[n][[;; , 2]], _?(# > 1 && OddQ[#] &)] == 1; Select[Range[500], q]
%o A377844 (PARI) is(k) = #select(x -> x>1 && x%2, factor(k)[, 2]) == 1;
%Y A377844 Subsequence of A295661.
%Y A377844 Subsequences: A065036, A143610, A163569.
%Y A377844 Cf. A060476, A065465, A325990, A376142, A377845.
%K A377844 nonn,easy
%O A377844 1,1
%A A377844 _Amiram Eldar_, Nov 09 2024