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

1,1

Links

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

Example

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

Mathematica

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

Prog

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

Crossrefs

Cf. A174734.

Sequence in context: A139361 A115329 A272645 * A140120 A303962 A304927

Adjacent sequences: A137699 A137700 A137701 * A137703 A137704 A137705

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Apr 27 2008

Status

approved