A165566 Primes p such that (p^2-1)/8-p is also prime.

17, 23, 31, 47, 73, 79, 103, 113, 127, 151, 167, 193, 199, 233, 241, 311, 313, 337, 401, 433, 479, 503, 521, 569, 577, 601, 631, 647, 719, 809, 823, 839, 863, 887, 911, 919, 953, 1031, 1049, 1087, 1129, 1151, 1193, 1201, 1217, 1231, 1249, 1303, 1433, 1439, 1487

Offset

1,1

Links

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

Formula

(a(n)^2-1)/8-a(n) = A165567(n).

Example

For p=17, (17^2-1)/8-17=19 is prime, which adds p=17 to the sequence.
For p=23, (23^2-1)/8-23=43 is prime, which adds p=23 to the sequence.

Mathematica

Select[Prime[Range[5, 1000]], PrimeQ[(#^2 - 1) / 8 - #]&] (* Vincenzo Librandi, Apr 10 2013 *)

Prog

(Magma) [p: p in PrimesInInterval(7, 1500) | IsPrime(((p^2-1) div 8) - p)]; // Vincenzo Librandi, Apr 10 2013

Crossrefs

Cf. A165567.

Sequence in context: A217044 A145484 A080830 * A072184 A377172 A107644

Adjacent sequences: A165563 A165564 A165565 * A165567 A165568 A165569

Keyword

nonn,easy

Author

Vincenzo Librandi, Sep 22 2009

Extensions

Edited and extended by R. J. Mathar, Sep 25 2009

Status

approved