A025584 Primes p such that p-2 is not a prime.

2, 3, 11, 17, 23, 29, 37, 41, 47, 53, 59, 67, 71, 79, 83, 89, 97, 101, 107, 113, 127, 131, 137, 149, 157, 163, 167, 173, 179, 191, 197, 211, 223, 227, 233, 239, 251, 257, 263, 269, 277, 281, 293, 307, 311, 317, 331, 337, 347, 353, 359, 367, 373, 379, 383, 389, 397, 401

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

Primes p (for p>=11) such that sigma(p-2) > p. - Benoit Cloitre, Feb 08 2002

Prime numbers that are not the sum of two smaller prime numbers. - Tomas Xordan, May 10 2007

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Crossrefs

Complement of A006512 in A000040.

Cf. A014092.

Programs

Magma

[p: p in PrimesUpTo(420) | not IsPrime(p-2)]; // Vincenzo Librandi, Jul 26 2013

Mathematica

Select[ Prime /@ Range[100], ! PrimeQ[# - 2] &] (* Jean-François Alcover, Apr 19 2013 *)

PARI

lista(nn) = forprime(p=2, nn, if (!isprime(p-2), print1(p, ", "));); \\ Michel Marcus, Dec 05 2015

Formula

a(n) ~ n log n. - Charles R Greathouse IV, Jan 10 2013

Extensions

Better description from Vladeta Jovovic, Dec 14 2002