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 A058656 #19 Mar 13 2025 08:56:00
%S A058656 1,1,2,1,2,1,2,1,2,1,2,1,2,3,8,1,2,1,2,1,2,1,2,1,2,3,2,1,2,1,2,1,2,1,
%T A058656 12,1,2,3,8,1,2,1,2,5,2,1,2,1,2,1,4,1,2,1,8,3,2,1,2,1,2,3,4,1,6,1,2,1,
%U A058656 2,1,2,1,2,3,4,1,6,1,2,1,2,1,2,1,2,3,8,1,2,1,4,1,2,1,24,1,2,3,20,1,2,1
%N A058656 a(n) = gcd(n+1, phi(n)).
%C A058656 Compare sequences gcd(x, phi(n)), where x = n-1, n, or n+1.
%H A058656 Amiram Eldar, <a href="/A058656/b058656.txt">Table of n, a(n) for n = 1..10000</a>
%e A058656 For n = 12, 13, 14, 15: n+1 = 13, 14, 15, 16; phi(n) = 4, 12, 12, 8; a(n) = gcd(13,4), gcd(14,12), gcd(15,12), gcd(16,8) = 1, 2, 3, 8, respectively.
%t A058656 Table[GCD[n+1,EulerPhi[n]],{n,110}] (* _Harvey P. Dale_, Nov 17 2011 *)
%o A058656 (PARI) a(n) = gcd(n+1, eulerphi(n)); \\ _Amiram Eldar_, Mar 13 2025
%Y A058656 Cf. A000010, A009195, A058515.
%K A058656 nonn
%O A058656 1,3
%A A058656 _Labos Elemer_, Dec 28 2000
%E A058656 Offset corrected by _Sean A. Irvine_, Aug 11 2022