A111001 Numbers n such that 23*n^2 - 25 is prime.

2, 8, 14, 48, 54, 56, 58, 78, 84, 92, 96, 106, 128, 142, 154, 156, 174, 184, 212, 222, 238, 252, 272, 282, 288, 342, 362, 366, 372, 378, 398, 418, 436, 448, 454, 464, 474, 488, 496, 516, 518, 524, 526, 532, 546, 554, 574, 594, 604, 618, 624, 638, 656, 664, 702

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Example

If n=92 then (23*n^2) - 25 = 194647 (prime).

Mathematica

Select[Range[1000], PrimeQ[23#^2-25]&] (* Harvey P. Dale, Jun 10 2014 *)

Prog

(Magma) [n: n in [2..100000] |IsPrime((23*n^2)-25)] - Vincenzo Librandi, Nov 13 2010
(PARI) is(n)=isprime(23*n^2-25) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A333053 A333054 A119752 * A055258 A277649 A192777

Adjacent sequences: A110998 A110999 A111000 * A111002 A111003 A111004

Keyword

nonn,easy

Author

Parthasarathy Nambi, Sep 30 2005

Status

approved