A195351 Numbers k such that there are no primes in the range [2^k-k, 2^k+k].

0, 25, 27, 45, 49, 97, 99, 113, 139, 176, 186, 208, 216, 227, 232, 259, 298, 309, 332, 358, 362, 364, 387, 490, 631, 659, 662, 676, 698, 705, 718, 726, 737, 747, 781, 849, 860, 862, 901, 913, 918, 936, 958, 965, 966, 992, 998

Offset: 1

Author

Juri-Stepan Gerasimov, Sep 16 2011

Keywords

• nonn

Comments

If a(n) is prime then it is not in A000043. - Alonso del Arte, Oct 07 2011

Crossrefs

Cf. A192454.

Programs

Mathematica

Select[Range[0, 49], PrimePi[2^# - # - 1] == PrimePi[2^# + #] &] (* Alonso del Arte, Oct 07 2011 *)

Formula

A192454(a(n))=0.