cp's OEIS Frontend

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.

A375076 Numbers whose prime factorization exponents include at least one 1, at least one 3 and no other exponents.

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%I A375076 #10 Jul 30 2024 14:37:02
%S A375076 24,40,54,56,88,104,120,135,136,152,168,184,189,232,248,250,264,270,
%T A375076 280,296,297,312,328,344,351,375,376,378,408,424,440,456,459,472,488,
%U A375076 513,520,536,552,568,584,594,616,621,632,664,680,686,696,702,712,728,744,750
%N A375076 Numbers whose prime factorization exponents include at least one 1, at least one 3 and no other exponents.
%C A375076 First differs from its subsequence A360793 at n = 79: a(79) = 1080 = 2^3 * 3^3 * 5 is not a term of A360793.
%C A375076 Numbers k such that the set of distinct prime factorization exponents of k (row k of A136568) is {1, 3}.
%C A375076 The asymptotic density of this sequence is ((zeta(6)/zeta(3)) * Product_{p prime} (1 + 2/p^3 - 1/p^4 + 1/p^5) - 1)/zeta(2) = 0.076359822332835689478... .
%H A375076 Amiram Eldar, <a href="/A375076/b375076.txt">Table of n, a(n) for n = 1..10000</a>
%H A375076 <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a>.
%t A375076 Select[Range[750], Union[FactorInteger[#][[;; , 2]]] == {1, 3} &]
%o A375076 (PARI) is(k) = Set(factor(k)[,2]) == [1, 3];
%Y A375076 Equals A336591 \ (A005117 UNION A062838).
%Y A375076 Subsequences: A065036, A360793.
%Y A375076 Cf. A002117, A013661, A013664, A136568.
%K A375076 nonn,easy
%O A375076 1,1
%A A375076 _Amiram Eldar_, Jul 29 2024