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A145471 Primes p such that (5+p)/2 is prime. 20
5, 17, 29, 41, 53, 89, 101, 113, 137, 173, 197, 257, 269, 293, 353, 389, 449, 461, 509, 521, 557, 617, 701, 761, 773, 797, 857, 881, 929, 953, 977, 1013, 1109, 1181, 1193, 1229, 1277, 1289, 1301, 1361, 1433, 1481, 1613, 1637, 1709, 1721, 1877, 1889, 1901 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All these primes are congruent to 1 mod 4 and to 5 mod 12.

LINKS

Table of n, a(n) for n=1..49.

MATHEMATICA

aa = {}; k = 5; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}]; aa

Select[Prime[Range[500]], PrimeQ[(5+#)/2]&]  *( From Harvey P. Dale, Apr 23 2011 *)

PROG

(PARI) forprime(p=2, 1e4, if(p%12!=5, next); if(isprime(p\2+3), print1(p", "))) \\ Charles R Greathouse IV, Jul 16, 2011

CROSSREFS

Cf. A092109.

Sequence in context: A017581 A068230 A040117 * A126193 A074965 A145475

Adjacent sequences:  A145468 A145469 A145470 * A145472 A145473 A145474

KEYWORD

nonn

AUTHOR

Artur Jasinski, Oct 11 2008

STATUS

approved

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Last modified November 23 18:50 EST 2014. Contains 249865 sequences.