A087697 Numbers k such that k + 7 and k - 7 are both prime.

10, 12, 24, 30, 36, 54, 60, 66, 90, 96, 120, 144, 156, 174, 186, 204, 234, 264, 270, 276, 300, 324, 360, 366, 390, 426, 450, 456, 516, 564, 570, 594, 600, 606, 624, 654, 666, 684, 726, 750, 780, 804, 816, 846, 870, 960, 984, 990

Offset: 1

Author

Zak Seidov, Sep 27 2003

Keywords

• nonn
• easy

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A014574, A087678, A087679, A087680, A087681, A087682, A087683, A087695, A087696, A088767.

Programs

Magma

[n: n in [5..1000] | IsPrime(n-7) and IsPrime(n+7)]; // Vincenzo Librandi, Jul 23 2018

Maple

select(t -> isprime(t+7) and isprime(t-7), [seq(i,i=8..1000,2)]); # Robert Israel, Jul 22 2018

Mathematica

Rest[Select[Range[1000], PrimeQ[# - 7] && PrimeQ[# + 7] &]] (* Vincenzo Librandi, Jul 23 2018 *)

PARI

isok(n) = isprime(n-7) && isprime(n+7); \\ Michel Marcus, Jul 23 2018