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 A166142 #12 Aug 06 2018 22:39:15
%S A166142 1,1,1,1,1,6,1,1,1,10,1,6,1,14,15,1,1,6,1,10,21,22,1,6,1,26,1,14,1,
%T A166142 900,1,1,33,34,35,6,1,38,39,10,1,1764,1,22,15,46,1,6,1,10,51,26,1,6,
%U A166142 55,14,57,58,1,900,1,62,21,1,65,4356,1,34,69,4900,1,6,1,74,15,38,77,6084,1,10
%N A166142 Row products of A166141; Product of such divisors of n that are squarefree and have an even number of prime factors.
%H A166142 Antti Karttunen, <a href="/A166142/b166142.txt">Table of n, a(n) for n = 1..65537</a>
%F A166142 a(n) = Product_{d|n} A080304(d). - _Antti Karttunen_, Aug 06 2018
%e A166142 For n = 30 = 2*3*5, all its divisors [1, 2, 3, 5, 6, 10, 15, 30] are squarefree, but only 1, 6, 10 and 15 have an even number of prime factors, thus a(30) = 1*6*10*15 = 900. - _Antti Karttunen_, Aug 06 2018
%o A166142 (PARI) A166142(n) = { my(m=1); fordiv(n,d,m *= if(moebius(d) > 0,d,1)); (m); }; \\ _Antti Karttunen_, Aug 06 2018
%Y A166142 Cf. A080304, A166141, A014963.
%K A166142 nonn
%O A166142 1,6
%A A166142 _Mats Granvik_, Oct 08 2009
%E A166142 Alternative definition added to the name by _Antti Karttunen_, Aug 06 2018