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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
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 *)
Select[Prime[Range[8000]], AllTrue[{(#-1)/2, (#+23)/2, #+24}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 31 2019 *)
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
Sequence in context: A005111 A225550 A179629 * A044125 A044506 A033217
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified July 18 00:08 EDT 2024. Contains 374377 sequences. (Running on oeis4.)