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 A176359 #19 Jul 22 2024 15:24:34
%S A176359 27000,74088,189000,287496,297000,343000,351000,370440,459000,474552,
%T A176359 513000,621000,783000,814968,837000,963144,999000,1029000,1061208,
%U A176359 1107000,1157625,1161000,1259496,1269000,1323000,1331000,1407672,1431000,1437480,1481544,1593000,1647000,1704024,1809000,1852200,1917000,1971000,2012472,2079000,2133000,2148552
%N A176359 Numbers with at least three 3s in their prime signature.
%C A176359 In other words, if the canonical prime factorization of a term into prime powers is Product p(i)^e(i), then e(i) = 3 for at least three values of i.
%C A176359 The asymptotic density of this sequence is 1 - (1 + s(1) + s(1)^2/2 - s(2)/2) * Product_{p prime} (1-1/p^3+1/p^4) = 0.000018992895371889141564..., where s(k) = Sum_{p prime} ((p-1)/(p^4-p+1))^k. - _Amiram Eldar_, Jul 22 2024
%H A176359 Amiram Eldar, <a href="/A176359/b176359.txt">Table of n, a(n) for n = 1..10000</a>
%e A176359 27000 is a term since 27000 = 2^3 * 3^3 * 5^3.
%e A176359 74088 is a term since 74088 = 2^3 * 5^3 * 7^3.
%t A176359 f[n_]:=Count[Last/@FactorInteger[n],3]>2; Select[Range[10!],f]
%o A176359 (PARI) is(n) = #select(x -> x == 3, factor(n)[, 2]) > 2; \\ _Amiram Eldar_, Jul 22 2024
%Y A176359 Cf. A000578, A001235, A176297, A176313, A176350.
%Y A176359 Subsequence of A109399.
%K A176359 nonn
%O A176359 1,1
%A A176359 _Vladimir Joseph Stephan Orlovsky_, Dec 07 2010
%E A176359 Edited by _Matthew Vandermast_, Dec 09 2010