1,2

Table of n, a(n) for n=1..37.

For p = 2 and k = 1, q = 2^0+2^1 = 1+2 = 3 is prime, hence 3-2 = 1 is in the sequence.

For p = 3 and k = 6, q = 3^0+3^1+3^2+3^3+3^4+3^5+3^6 = 1+3+9+27+81+243+729 = 1093 is prime, hence 1093-3 = 1090 is in the sequence.

Cf. A000040 (prime numbers).

Sequence in context: A038252 A211865 A083010 * A290055 A066872 A301537

Adjacent sequences: A166385 A166386 A166387 * A166389 A166390 A166391

nonn

Juri-Stepan Gerasimov, Oct 13 2009

Edited and extended by Klaus Brockhaus, Oct 16 2009

approved