A260376 Values of n such that prime(prime(n)) + n is a prime number.

2, 6, 16, 20, 30, 42, 78, 90, 92, 102, 108, 118, 124, 126, 128, 132, 136, 150, 160, 166, 180, 182, 186, 194, 196, 202, 206, 210, 214, 230, 270, 280, 294, 348, 356, 358, 366, 370, 374, 378, 418, 436, 456, 458, 472, 474, 478, 492, 522, 546, 556, 560, 570, 584, 586, 590

Offset: 1

Author

Altug Alkan, Aug 29 2015

Keywords

• nonn
• easy

Comments

Inspired by A061068.

Obviously, sequence only can include even numbers.

Initial primes of the form prime(prime(n)) + n are 7, 47, 257, 373, 647, 1129, 2797, 3389, 3499, 4129, 4447.

Examples

			For n=2, prime(prime(2)) + 2 = prime(3) + 2 = 7. 7 is a prime number.
		

Crossrefs

Cf. A006450.

Programs

Magma

[n: n in [1..600] | IsPrime(NthPrime(NthPrime(n))+n)]; // Vincenzo Librandi, Aug 30 2015

Mathematica

Select[Range[600], PrimeQ[Prime[Prime[#]] + #] &] (* Vincenzo Librandi, Aug 30 2015 *)

PARI

for(n=1, 1e3, if(isprime(prime(prime(n))+n), print1(n", ")))

Perl

use ntheory ":all"; my @p = grep { is_prime(nth_prime(nth_prime($))+$) } 1..10000; say join ", ", @p; # Dana Jacobsen, Sep 02 2015