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A158238
Primes p such that (p-7)/8 and 8p + 7 are both prime.
1
23, 47, 863, 1103, 1439, 1583, 1823, 2879, 3359, 4943, 5279, 6719, 7823, 8783, 9743, 11279, 11903, 12479, 13103, 16703, 18719, 19583, 20399, 20879, 21503, 23279, 23663, 25343, 26399, 27743, 29759, 33119, 35279, 38303, 39359, 39503, 41183
OFFSET
1,1
LINKS
FORMULA
23, (23-7)/8=2, and 8*23+7=191 are all prime.
MATHEMATICA
Select[Prime[Range[5000]], AllTrue[{(#-7)/8, 8#+7}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 24 2015 *)
PROG
(PARI) isok(p) = isprime(p) && isprime(8*p+7) && ((p % 8)==7) && isprime((p-7)/8); \\ Michel Marcus, Oct 16 2013
CROSSREFS
Cf. A023231 Numbers n such that n and 8n + 7 are both prime.
Sequence in context: A084667 A255596 A157358 * A328799 A333115 A042056
KEYWORD
nonn
AUTHOR
Zak Seidov, Mar 14 2009
STATUS
approved