A057467 GCD of n-th and (n+1)-st term in the sequence of first differences between primes, A001223.

1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 6, 2, 2, 2, 2, 2, 2, 12, 4, 2, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 4, 4, 4, 4, 4, 2, 6, 2, 2, 6, 2, 2, 6, 2, 2

Offset: 1

Author

Labos Elemer, Dec 06 2000

Keywords

• nonn
• easy

Crossrefs

Cf. A001223.

Programs

Mathematica

Map[GCD @@ # &, Partition[#, 2, 1] &@ Differences@ Prime@ Range@ 100] (* Michael De Vlieger, Feb 18 2017 *)

Formula

a(n) = gcd( A001223(n+1), A001223(n) ).