A165637 Primes p such that (p^2-3)/2 is not a prime number.

2, 17, 43, 53, 59, 61, 71, 83, 89, 107, 113, 127, 131, 137, 139, 149, 163, 167, 173, 179, 181, 191, 193, 199, 223, 229, 241, 251, 269, 271, 277, 281, 283, 311, 313, 317, 347, 373, 379, 383, 401, 419, 421, 431, 433, 439, 457, 461, 467, 479, 499, 503, 523, 541, 557, 563

Offset

1,1

Links

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

Formula

A000040 \ A110589. - R. J. Mathar, Sep 26 2009

Example

For p=17=a(2), (17^2-3)/2=143 is not a prime. For p=43=a(3), (43^2-3)/2=923 is not a prime.

Mathematica

Select[Prime[Range[200]], !PrimeQ[(#^2 - 3) / 2]&] (* Harvey P. Dale, Dec 09 2011 *)

Prog

(Magma) [p: p in PrimesUpTo(600)| not IsPrime((p^2-3) div 2)]; // Vincenzo Librandi, Sep 12 2013

Crossrefs

Sequence in context: A256145 A096172 A120745 * A100271 A046973 A226488

Adjacent sequences: A165634 A165635 A165636 * A165638 A165639 A165640

Keyword

nonn,easy

Author

Vincenzo Librandi, Sep 23 2009

Extensions

Extended by R. J. Mathar, Sep 26 2009

Status

approved