A167464 Primes p such that 20*p+19 is composite.

5, 7, 13, 19, 31, 37, 43, 47, 53, 59, 61, 67, 73, 79, 83, 89, 97, 103, 107, 109, 113, 127, 131, 137, 139, 151, 157, 163, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 241, 257, 271, 277, 283, 307, 311, 313, 331, 337, 349, 359, 367, 373, 379, 383, 389

Offset: 1

Author

Vincenzo Librandi, Nov 04 2009

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A157977.

Programs

Magma

[p: p in PrimesUpTo(400) | not IsPrime(20*p+19)]; // Vincenzo Librandi, Feb 15 2014

Mathematica

Select[Prime[Range[500]], !PrimeQ[20 # + 19] &]
(* Vincenzo Librandi, Feb 15 2014 *)