A093706 - OEIS

A093706

Primes p such that (pp'-1)/2 is prime, where p' denotes the next prime after p.

3, 5, 11, 29, 41, 71, 137, 281, 461, 599, 641, 787, 827, 881, 1091, 1129, 1301, 1409, 1607, 1627, 1951, 2129, 2267, 2357, 2381, 2557, 2687, 2887, 2917, 3469, 3527, 3557, 3581, 3967, 4127, 4229, 4337, 4547, 4889, 5009, 5309, 5741, 6131, 6133, 6247, 6343

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

MATHEMATICA

Prime[ Select[ Range[850], PrimeQ[(Prime[ # ]Prime[ # + 1] - 1)/2] &]]

Transpose[Select[Partition[Prime[Range[900]], 2, 1], PrimeQ[ (Times@@#- 1)/2]&]][[1]] (* Harvey P. Dale, Sep 17 2011 *)

PROG

(PARI) isA093706(n) = if(n<3, 0, isprime(n) && isprime((n*nextprime(n+1)-1)/2)) \\ Michael B. Porter, Dec 15 2009

CROSSREFS

Cf. A048797.