A110558 Numbers n such that (n^2-8)/8 is prime.

8, 12, 16, 24, 28, 32, 40, 44, 52, 60, 68, 72, 84, 88, 96, 100, 112, 136, 144, 152, 156, 164, 168, 172, 180, 184, 196, 200, 208, 224, 236, 248, 252, 256, 276, 292, 304, 320, 324, 340, 348, 364, 368, 380, 392, 408, 432, 436, 448, 452, 460, 472, 500, 504, 508

Offset: 1

Author

Pierre CAMI, Sep 12 2005

Keywords

• nonn

Comments

These numbers need to be of the form 4*j then (16*j^2-8)/8 = 2*j^2-1.

A066436 gives resulting primes p such that 8p+8 is square. - Ray Chandler, Sep 15 2005

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A066049, A066436, A090697, A091176.

Programs

Mathematica

Select[Range[510],PrimeQ[(#^2-8)/8]&] (* Harvey P. Dale, Feb 03 2011 *)

PARI

is(n)=isprime((n^2-8)/8) \\ Charles R Greathouse IV, Feb 20 2017

Formula

a(n) = 2*A090697(n) = 4*A066049(n). - Ray Chandler, Sep 15 2005

Extensions

Extended by Ray Chandler, Sep 15 2005