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%I #14 May 05 2017 08:15:22
%S 1,2,3,4,1,2,1,4,3,10,1,2,1,2,3,2,1,2,1,4,1,2,1,6,1,2,1,4,1,6,1,4,3,2,
%T 5,4,1,2,3,2,1,14,1,2,9,2,1,16,1,10,3,4,1,18,1,8,3,2,1,6,1,2,7,8,1,6,
%U 1,2,3,70,1,72,1,2,5,4,1,2,1,10,3,2,1,14,5,2,3,2,1,2,13,4,1,2,5,24,1,2,1,2
%N a(n) = gcd(prime(n)+1, n).
%H Ivan Neretin, <a href="/A084310/b084310.txt">Table of n, a(n) for n = 1..10000</a>
%p A084310:= n-> igcd(ithprime(n)+1,n): seq(A084310(n), n=1..150); # _Wesley Ivan Hurt_, Jan 27 2017
%t Table[GCD[Prime[w]+1, w], {w, 128}]
%o (PARI) a(n) = gcd(prime(n)+1, n); \\ _Michel Marcus_, Jan 27 2017
%Y Cf. A084309, A084311, A084312, A084313, A084314, A084315, A084316.
%K nonn,easy
%O 1,2
%A _Labos Elemer_, Jun 13 2003