1,2

Table of n, a(n) for n=1..90.

a(1) = 1 because p(1)*p(2) + 1 = 2*3 + 1 = 7 -> prime

NextPrime[#]-#&/@Times@@@Partition[Prime[Range[100]], 2, 1] (* Harvey P. Dale, May 28 2013 *)

Sequence in context: A023957 A224964 A278165 * A285713 A278230 A344859

Adjacent sequences: A074925 A074926 A074927 * A074929 A074930 A074931

nonn

Zak Seidov, Oct 02 2002

approved