A063086 - OEIS

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A063086

a(n) = gcd(1 + prime(n+1), 1 + prime(n)).

1, 2, 2, 4, 2, 2, 2, 4, 6, 2, 2, 2, 2, 4, 6, 6, 2, 2, 4, 2, 2, 4, 6, 2, 2, 2, 4, 2, 2, 2, 4, 6, 2, 10, 2, 2, 2, 4, 6, 6, 2, 2, 2, 2, 2, 4, 4, 4, 2, 2, 6, 2, 2, 6, 6, 6, 2, 2, 2, 2, 2, 14, 4, 2, 2, 2, 2, 2, 2, 2, 6, 8, 2, 2, 4, 6, 2, 2, 2, 10, 2, 2, 2, 2, 4, 6, 2, 2, 2, 4, 12, 8, 4, 4, 4, 6, 6, 2, 2, 2, 2, 6

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

EXAMPLE

n=34: gcd(1 + 139, 1 + 149) = 10 = a(34).

MATHEMATICA

GCD[First[#]+1, Last[#]+1]&/@ Partition[Prime[Range[110]], 2, 1] (* Harvey P. Dale, May 02 2012 *)

PROG

(PARI) a(n)={gcd(1 + prime(n+1), 1 + prime(n))} \\ Harry J. Smith, Aug 17 2009

CROSSREFS