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A274381 Safe primes p such that p + 24 is also a safe prime. 1
23, 59, 83, 359, 479, 563, 839, 863, 1283, 2039, 2879, 2999, 3779, 4259, 4679, 5483, 7703, 10079, 12203, 13103, 23603, 26903, 27803, 30323, 31583, 33623, 35339, 41519, 43403, 44519, 44939, 53759, 55079, 57119, 57899, 58043, 65123, 66359, 70139, 70199, 76379, 77723, 79943 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

John Cerkan, Table of n, a(n) for n = 1..10000

FORMULA

{ x | both x and x + 24 are safe primes }.

EXAMPLE

83 is a safe prime and so is 83 + 24 = 107.

4679 is a safe prime and so is 4679 + 24 = 4703.

MAPLE

A274381:=n->`if`(type((n-1)/2, prime) and isprime(n+24) and isprime(n) and type((n+23)/2, prime), n, NULL): seq(A274381(n), n=1..10^5); # Wesley Ivan Hurt, Jun 25 2016

MATHEMATICA

Select[Prime@ Range[10^4], PrimeQ[(# - 1)/2] && PrimeQ[# + 24] && PrimeQ[(23 + #)/2] &] (* Giovanni Resta, Jun 23 2016 *)

PROG

(PARI) lista(nn) = forprime(p=3, nn, if (isprime((p-1)/2) && isprime(q=p+24) && isprime((q-1)/2), print1(p, ", "))); \\ Michel Marcus, Jun 23 2016

CROSSREFS

Cf. A005385, A033560, A059323.

Sequence in context: A005111 A225550 A179629 * A044125 A044506 A033217

Adjacent sequences:  A274378 A274379 A274380 * A274382 A274383 A274384

KEYWORD

nonn

AUTHOR

Debapriyay Mukhopadhyay, Jun 23 2016

STATUS

approved

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Last modified April 24 04:00 EDT 2019. Contains 322406 sequences. (Running on oeis4.)