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 A382965 #9 Apr 11 2025 08:46:18
%S A382965 1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,
%T A382965 1,1,1,1,1,1,1,2,1,2,1,1,1,1,1,2,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,2,
%U A382965 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
%N A382965 The number of non-unitary prime divisors of the n-th cubefree number that is not squarefree.
%C A382965 The positive terms of A376366.
%H A382965 Amiram Eldar, <a href="/A382965/b382965.txt">Table of n, a(n) for n = 1..10000</a>
%F A382965 a(n) = A056170(A067259(n)).
%F A382965 a(n) = A046660(A067259(n)).
%F A382965 a(n) = A369427(A067259(n)).
%F A382965 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = (zeta(2)/(zeta(2)-zeta(3))) * Sum_{p prime} ((p-1)/(p^3-1)) = 1.10872412837037270926... .
%t A382965 f[k_] := If[k == 1, Nothing, Module[{e = FactorInteger[k][[;; , 2]]}, If[Max[e] == 2, Count[e, 2], Nothing]]]; Array[f, 150]
%o A382965 (PARI) list(lim) = {my(e); for(k = 2, lim, e = factor(k)[, 2]; if(vecmax(e) == 2, print1(#select(x -> x == 2, e), ", ")));}
%Y A382965 Cf. A002117, A046660, A056170, A067259, A013661, A369427, A376366, A382966, A382968.
%K A382965 nonn,easy
%O A382965 1,8
%A A382965 _Amiram Eldar_, Apr 10 2025