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 A326140 #8 Jun 10 2019 17:56:38
%S A326140 1,1,2,1,4,2,6,1,5,2,10,2,12,2,6,1,16,1,18,2,10,2,22,2,19,2,14,6,28,6,
%T A326140 30,1,18,2,22,1,36,2,22,2,40,2,42,2,12,2,46,2,41,1,30,6,52,2,38,2,34,
%U A326140 2,58,6,60,2,22,1,46,6,66,2,42,2,70,1,72,2,26,6,58,2,78,2,41,2,82,2,62,2,54,2,88,6,70,2,58,2
%N A326140 a(n) = gcd(A318878(n), A318879(n)).
%H A326140 Antti Karttunen, <a href="/A326140/b326140.txt">Table of n, a(n) for n = 1..20000</a>
%o A326140 (PARI) A326140(n) = { my(t=0, u=0); fordiv(n,d, d -= 2*eulerphi(d); if(d<0, t -= d, u += d)); gcd(t,u); };
%o A326140 (PARI)
%o A326140 A318878(n) = sumdiv(n,d,d=(2*eulerphi(d))-d; (d>0)*d);
%o A326140 A318879(n) = sumdiv(n,d,d=d-(2*eulerphi(d)); (d>0)*d);
%o A326140 A326140(n) = gcd(A318878(n), A318879(n));
%Y A326140 Cf. A033879, A083254, A318878, A318879, A326141.
%Y A326140 Cf. also A009194, A325385, A325813, A325975, A326046, A326047, A326048, A326056, A326057, A326060, A326062, A326129, A326130, A326144.
%K A326140 nonn
%O A326140 1,3
%A A326140 _Antti Karttunen_, Jun 09 2019