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 A114005 #15 Feb 23 2020 16:27:51
%S A114005 1,-2,-2,2,-2,6,-2,-2,2,6,-2,-10,-2,6,6,2,-2,-10,-2,-10,6,6,-2,14,2,6,
%T A114005 -2,-10,-2,-26,-2,-2,6,6,6,26,-2,6,6,14,-2,-26,-2,-10,-10,6,-2,-18,2,
%U A114005 -10,6,-10,-2,14,6,14,6,6,-2,62,-2,6,-10,2,6,-26,-2,-10,6,-26,-2,-50,-2,6,-10,-10,6,-26,-2,-18,2,6,-2,62,6,6,6,14,-2,62,6,-10,6,6,6
%N A114005 First column of number triangle A114004.
%C A114005 Moebius transform of A114006. - _Mats Granvik_, Jan 02 2009
%H A114005 Antti Karttunen, <a href="/A114005/b114005.txt">Table of n, a(n) for n = 1..10000</a>
%F A114005 a(1) = 1, for n > 1, a(n) = 2*A114006(n). - Corrected by _Antti Karttunen_, May 27 2017
%F A114005 a(1) = 1; a(n) = -2 * Sum_{d|n, d < n} a(d). - _Ilya Gutkovskiy_, Feb 23 2020
%o A114005 (PARI)
%o A114005 A050328(n) = if(1==n,n,sumdiv(n,d,if((d<n && issquarefree(n/d)),A050328(d),0)));
%o A114005 A114006(n) = ((-1)^bigomega(n) * A050328(n));
%o A114005 A114005(n) = if(1==n,n,2*A114006(n)); \\ _Antti Karttunen_, May 27 2017
%Y A114005 Cf. A050328, A114006.
%K A114005 easy,sign
%O A114005 1,2
%A A114005 _Paul Barry_, Nov 12 2005
%E A114005 More terms from _Antti Karttunen_, May 27 2017