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A023231 Primes p such that 8*p + 7 is also prime. 6
2, 3, 5, 23, 29, 47, 53, 59, 89, 107, 113, 137, 179, 197, 227, 233, 257, 263, 293, 317, 359, 389, 419, 509, 557, 587, 593, 599, 617, 653, 659, 683, 839, 857, 863, 887, 947, 977, 1013, 1097, 1103, 1163, 1193, 1217, 1223, 1229, 1259, 1277, 1283, 1307, 1319, 1409 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

For p = 3, 8*p + 7 = 31;

for p = 179, 8*p + 7 = 1439.

MAPLE

a := proc (n) if isprime(n) = true and isprime(8*n+7) = true then n else end if end proc: seq(a(n), n = 1 .. 1500); # Emeric Deutsch, Dec 30 2008

MATHEMATICA

Select[Prime@Range@500, PrimeQ[8 # + 7] &] (* Vincenzo Librandi, May 19 2014 *)

PROG

(MAGMA) [n: n in PrimesUpTo(1500) | IsPrime(8*n+7)]; // Vincenzo Librandi, Nov 20 2010

CROSSREFS

Cf. A139487, A007522.

Sequence in context: A041195 A042141 A122004 * A034470 A237812 A138170

Adjacent sequences:  A023228 A023229 A023230 * A023232 A023233 A023234

KEYWORD

nonn,easy

AUTHOR

David W. Wilson

EXTENSIONS

Edited by N. J. A. Sloane, Mar 11 2009 at the suggestion of R. J. Mathar

STATUS

approved

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Last modified July 27 10:31 EDT 2021. Contains 346304 sequences. (Running on oeis4.)