A165991 Numbers n such that 3 + 2^n is not prime.

0, 5, 8, 9, 10, 11, 13, 14, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 85, 86, 87

Offset

1,2

Comments

Complement of A057732.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Example

For n=0, 3+2^0=4 is not prime. n=5, 3+2^5=35=5*7, not prime. n=8, 3+2^8=259=7*37 not prime.

Mathematica

Select[Range[0, 100], !PrimeQ[3 + 2^#] &] (* Vincenzo Librandi, Oct 15 2012 *)

Prog

(Magma) [n: n in [0..100] |not IsPrime(3 + 2^n )]; // Vincenzo Librandi, Oct 15 2012

Crossrefs

Sequence in context: A259071 A205862 A293795 * A300331 A293271 A348046

Adjacent sequences: A165988 A165989 A165990 * A165992 A165993 A165994

Keyword

nonn,easy

Author

Vincenzo Librandi, Oct 03 2009

Extensions

Entries checked - R. J. Mathar, Oct 05 2009

Status

approved