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A090865 Primes p such that (p-1)/2 is prime if p == 3 (mod 4) or (p-1)/4 is prime if p == 1 (mod 4). 2
7, 11, 13, 23, 29, 47, 53, 59, 83, 107, 149, 167, 173, 179, 227, 263, 269, 293, 317, 347, 359, 383, 389, 467, 479, 503, 509, 557, 563, 587, 653, 719, 773, 797, 839, 863, 887, 983, 1019, 1109, 1187, 1229, 1283, 1307, 1319, 1367, 1439, 1487, 1493, 1523, 1619 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

MATHEMATICA

Select[Prime[Range[256]], PrimeQ[(#-1)/(5-Mod[#, 4])]& ] (* Jean-Fran├žois Alcover, Jul 16 2012 *)

PROG

(PARI) forprime(p=1, 1619, if (((p%4==3) && isprime((p-1)/2)==1) || ((p%4==1) && isprime((p-1)/4)), print1(p, ", "))) \\ Jinyuan Wang, Feb 09 2019

CROSSREFS

Subsequence of A058500.

Union of (A005385 \ {5}) and A090866.

Sequence in context: A297176 A155760 A058500 * A296716 A191062 A106079

Adjacent sequences:  A090862 A090863 A090864 * A090866 A090867 A090868

KEYWORD

nonn,changed

AUTHOR

Benoit Cloitre, Feb 12 2004

STATUS

approved

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Last modified February 23 08:00 EST 2019. Contains 320420 sequences. (Running on oeis4.)