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%I #12 Aug 11 2022 22:57:33
%S 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 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 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 a(n) = gcd(n+1, phi(n)).
%C Compare sequences gcd(x, phi(n)), where x = n-1, n, or n+1.
%e For n = 12, 13, 14, 15:
%e n+1 = 13, 14, 15, 16;
%e phi(n) = 4, 12, 12, 8;
%e a(n) = gcd(13,4), gcd(14,12), gcd(15,12), gcd(16,8) = 1, 2, 3, 8, respectively.
%t Table[GCD[n+1,EulerPhi[n]],{n,110}] (* _Harvey P. Dale_, Nov 17 2011 *)
%Y Cf. A000010, A009195, A058515.
%K nonn
%O 1,3
%A _Labos Elemer_, Dec 28 2000
%E Offset corrected by _Sean A. Irvine_, Aug 11 2022