A261538 Primes p such that p^9 + 2 is also prime.

11, 41, 101, 227, 461, 587, 641, 887, 977, 1097, 1217, 1559, 2039, 2129, 2357, 3221, 3491, 3677, 3917, 4019, 4547, 5009, 5261, 5279, 5639, 6221, 6359, 6599, 6719, 7187, 7907, 8147, 9767, 9929, 10211, 10391, 11177, 11549, 11801, 11939, 12197, 12671, 13907

Offset: 1

Author

Vincenzo Librandi, Aug 24 2015

Keywords

• nonn

Comments

All terms == 5 mod 6. Robert Israel, Aug 27 2015

Examples

			11 is in the sequence because 11^9 + 2 = 2357947693 is a prime.
		

Links

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

Crossrefs

Subsequence of A007528.

Cf. A000040.

Cf. similar sequences listed in A261536.

Programs

Magma

[p: p in PrimesUpTo(20000) | IsPrime(p^9+2)];

Maple

select(t -> isprime(t) and isprime(t^9+2), [seq(6*i-1, i=1..10^4)]); # Robert Israel, Aug 27 2015

Mathematica

Select[Prime[Range[2000]], PrimeQ[#^9 + 2] &]

PARI

forprime(p=2, 10^4, if (isprime(p^9+2), print1(p, ", "))) \\ Anders Hellström, Aug 27 2015

PARI

list(lim)=my(v=List(),t); forprime(p=2,lim, if(isprime(p^9+2), listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Aug 27 2015