0,1

The sequence is bounded, namely {a(n)} = {3, 5, 7}, because one of the numbers 2^n + 3, 2^n + 5, 2^n + 7 is divisible by 3. - Thomas Ordowski, Apr 11 2019

Table of n, a(n) for n=0..104.

A000079(20) + a(20) = 1048576 + 3 = 1048579 = 7*163*919.

Table[p := 2; While[PrimeQ[2^n + Prime[p]], p++ ]; Prime[p], {n, 0, 150}] (* Stefan Steinerberger, Mar 28 2006 *)

Cf. A000079, A000040.

Sequence in context: A238048 A010624 A019638 * A287660 A122001 A161327

Adjacent sequences: A116532 A116533 A116534 * A116536 A116537 A116538

nonn

Reinhard Zumkeller, Mar 27 2006

More terms from Stefan Steinerberger, Mar 28 2006

approved