A137702 Prime numbers p such that p +- ((p-1)/2) are primes.

5, 13, 73, 421, 541, 613, 661, 673, 1201, 1453, 2341, 2473, 2593, 3061, 3313, 4441, 4561, 5113, 6073, 6121, 6133, 8521, 8893, 9601, 9901, 10453, 11161, 11701, 12301, 12721, 13381, 13681, 13933, 15241, 15361, 15373, 15733, 16033, 16333, 16381

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Apr 27 2008

Keywords

• nonn
• easy

Examples

			(5-2, 5+2) are prime
(13-6, 13+6) are prime
		

Links

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

Crossrefs

Cf. A174734.

Programs

Mathematica

Select[Prime[Range[1000]], PrimeQ[#-(#-1)/2] && PrimeQ[#+(#-1)/2]&]

PARI

forprime(p=3,1e5,if(isprime(p+p\2)&isprime(p\2+1),print1(p", ")))