A173473 n-th prime^2-2*n is prime.

1, 2, 3, 4, 6, 10, 15, 16, 19, 22, 24, 28, 31, 46, 48, 49, 61, 66, 70, 88, 90, 91, 93, 94, 96, 97, 111, 114, 118, 126, 130, 136, 141, 157, 159, 160, 163, 171, 177, 196, 199, 201, 210, 211, 213, 216, 225, 238, 243, 255, 258, 279, 294, 300, 306, 309, 312, 315, 324, 330

Offset

1,2

Comments

Numbers n such that A001248(n)-A005843(n+1)=prime.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Example

1 is in the sequence because (1st prime)^2-2*1=2, which is prime;
2 is in the sequence because (2nd prime)^2-2*2=5, which is prime.

Mathematica

Select[Range[4000], PrimeQ[Prime[#]^2 - 2 #] &] (* Vincenzo Librandi, Apr 15 2014 *)

Prog

(PARI) isok(n) = isprime(prime(n)^2 - 2*n); \\ Michel Marcus, Apr 15 2014
(Magma) [n: n in [0..400] | IsPrime(NthPrime(n)^2-2*n)]; // Vincenzo Librandi, Apr 15 2014

Crossrefs

Cf. A001248, A005843.

Sequence in context: A240057 A279467 A094861 * A288807 A097699 A086990

Adjacent sequences: A173470 A173471 A173472 * A173474 A173475 A173476

Keyword

nonn

Author

Juri-Stepan Gerasimov, Feb 19 2010

Extensions

More terms from R. J. Mathar, Mar 01 2010

Status

approved