A165352 Primes of the form p + (p^2 - 1)/8, where p is also prime.

13, 53, 89, 151, 251, 701, 739, 859, 1429, 1709, 2143, 3001, 4751, 7019, 8513, 10151, 12401, 14533, 17203, 18719, 21319, 23869, 27259, 30133, 41039, 42193, 44549, 45751, 46663, 52973, 82619, 99233, 104651, 114479, 120293, 135979, 138599, 148783, 151523

Offset

1,1

Comments

Primes of the form k+(k^2-1)/8, where k >0 are prime or composite, are the superset 13, 19, 43, 53, 89, 103 etc.

Links

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

Formula

a(n) = A165353(n)+(A165353(n)^2-1)/8.

Mathematica

Select[Table[p + (p^2 - 1)/8, {p, Prime[Range[200]]}], PrimeQ] (* Vincenzo Librandi, Oct 12 2012 *)

Prog

(Magma) [a: p in PrimesInInterval(3, 1200) | IsPrime(a) where a is p + (p^2 - 1) div 8 ]; // Vincenzo Librandi, Oct 12 2012
(PARI) forprime(p=3, 1e4, if(isprime(t=p^2>>3+p), print1(t", "))) \\ Charles R Greathouse IV, May 15 2013

Crossrefs

Cf. A165353, A165354.

Sequence in context: A056255 A141885 A262447 * A262287 A307749 A031905

Adjacent sequences: A165349 A165350 A165351 * A165353 A165354 A165355

Keyword

nonn,easy

Author

Vincenzo Librandi, Sep 16 2009

Extensions

More terms from R. J. Mathar, Sep 21 2009

Status

approved