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 A077103 #11 Oct 27 2019 05:16:33
%S A077103 1,2,12,15,30,39,44,55,56,76,78,87,95,99,110,111,125,140,143,147,159,
%T A077103 171,172,174,175,183,184,190,198,215,216,222,236,247,250,252,264,268,
%U A077103 286,287,294,295,303,315,318,319,327,332,335,336,342,350,357,363,364
%N A077103 Numbers n such that gcd(a,b) is not equal to gcd(a+b,a-b), where a=sigma(n)=A000203(n) and b=phi(n)=A000010(n).
%F A077103 gcd(A000010(n), A000203(n)) is not equal to gcd(A065387(n), A051612(n)); or A055008(n) is not equal to A077099(n).
%e A077103 n=76: a=sigma(76)=140, b=phi(76)=36, a+b=176, a-b=104, gcd(a,b) = gcd(140,36) = 4 < gcd(a+b,a-b) = gcd(176,104) = 8.
%t A077103 Do[s=GCD[a=DivisorSigma[1, n], b=EulerPhi[n]]; s1=GCD[a+b, a-b]; If[ !Equal[s, s1], Print[{n, a, b, a+b, a-b, s, s1, s1/s}]], {n, 1, 1000}]
%Y A077103 Cf. A000010, A000203, A051612, A065387, A055008, A077099.
%K A077103 nonn
%O A077103 1,2
%A A077103 _Labos Elemer_, Nov 12 2002