A280083 Numbers k such that (2^k + 1)/(2 - (-1)^k) is a prime.

0, 2, 3, 4, 5, 7, 8, 11, 13, 16, 17, 19, 23, 31, 43, 61, 79, 101, 127, 167, 191, 199, 313, 347, 701, 1709, 2617, 3539, 5807, 10501, 10691, 11279, 12391, 14479, 42737, 83339, 95369, 117239, 127031, 138937, 141079, 267017, 269987, 374321, 986191, 4031399

Offset: 1

Author

Thomas Ordowski, Dec 25 2016

Keywords

• nonn

Crossrefs

Cf. A000978, A019434.

Programs

Mathematica

Select[Range[0, 10^3], PrimeQ[(2^# + 1)/(2 - (-1)^#)] &] (* Michael De Vlieger, Dec 25 2016 *)