A096817 Numbers k such that 2^k - 11 is prime.

4, 6, 10, 18, 42, 78, 94, 114, 190, 322, 546, 3894, 10318, 11650, 12474, 20994, 61810, 103882, 296010, 636930, 653638, 926766

Offset: 1

Author

Labos Elemer, Jul 13 2004

Keywords

• nonn
• more

Comments

All terms are even since for odd k, 2^k - 11 is divisible by 3.

Examples

			k = 6: 64 - 11 = 53 is prime.
		

Links

• Henri Lifchitz and Renaud Lifchitz, Search for 2^n-11, PRP Top Records.

Crossrefs

Cf. A096502.

Cf. Sequences of numbers k such that 2^k - d is prime: A000043 (d=1), A050414 (d=3), A059608 (d=5), A059609 (d=7), A059610 (d=9), this sequence (d=11), A096818 (d=13), A059612 (d=15), A059611 (d=17), A096819 (d=19), A096820 (d=21), A057220 (d=23), A356826 (d=29).

Programs

Mathematica

Select[Range[4,20000],PrimeQ[2^#-11]&] (* Vladimir Joseph Stephan Orlovsky, Feb 26 2011*)

Extensions

a(13)-a(16) from Max Alekseyev, a(17)-a(18) from Henri Lifchitz, added by Max Alekseyev, Feb 09 2012

a(19) from Lelio R Paula, added by Max Alekseyev, Oct 24 2013

a(20)-a(22) from Stefano Morozzi, added by Elmo R. Oliveira, Nov 16 2023