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A258992 Primes p such that p^2 - 8 is also prime. 1
5, 7, 11, 17, 19, 23, 31, 37, 53, 67, 101, 103, 149, 163, 173, 191, 227, 229, 241, 257, 269, 271, 313, 347, 353, 359, 367, 373, 383, 431, 467, 479, 487, 523, 541, 563, 577, 599, 613, 619, 647, 653, 661, 733, 761, 773, 823, 829, 859, 863, 919, 941, 1061, 1087 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The first appearances of 2..6 consecutive primes in the sequence are: {31,37}, {5, 7, 11}, {353, 359, 367, 373}, {1293199, 1293203, 1293233, 1293239, 1293247}, {3982031, 3982037, 3982057, 3982067, 3982073, 3982079}.

Initial terms of the sets of exactly 6 consecutive primes: {3982031, 5495989, 33057589, 255414437, 495180067, 558985507}.

LINKS

K. D. Bajpai, Table of n, a(n) for n = 1..10000

EXAMPLE

From K. D. Bajpai, Jun 18 2015: (Start)

a(3) = 11:  11^2 -8 = 113; both are prime.

a(4) = 17:  17^2 -8 = 281; both are prime.

(End)

MATHEMATICA

Select[Prime[Range[5000]], PrimeQ[#^2-8]&]  (* K. D. Bajpai, Jun 18 2015 *)

PROG

(PARI) lista(nn) = forprime(p=2, nn, if (isprime(p^2-8), print1(p, ", "))); \\ Michel Marcus, Jun 16 2015

(MAGMA)  [p: p in PrimesUpTo(5000) | IsPrime(p^2-8)];  // K. D. Bajpai, Jun 18 2015

CROSSREFS

Cf. A062718, A137270.

Sequence in context: A180952 A073681 A155772 * A020582 A106863 A200569

Adjacent sequences:  A258989 A258990 A258991 * A258993 A258994 A258995

KEYWORD

nonn

AUTHOR

Zak Seidov, Jun 16 2015

STATUS

approved

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Last modified November 16 22:43 EST 2018. Contains 317275 sequences. (Running on oeis4.)