A110998 Numbers n such that 23*n^2 - 9 is prime.

2, 4, 16, 38, 40, 44, 70, 82, 86, 88, 116, 128, 130, 142, 152, 158, 170, 178, 194, 224, 226, 238, 262, 268, 298, 304, 310, 320, 346, 352, 362, 364, 368, 392, 406, 418, 434, 446, 452, 458, 460, 472, 478, 490, 494

Offset

1,1

Links

Table of n, a(n) for n=1..45.

Example

If n=88 then 23*n^2 - 9 = 178103 (prime).

Mathematica

Select[Range[500], PrimeQ[(23#^2 - 9)] &] (* Stefan Steinerberger, Feb 28 2006 *)

Prog

(PARI) is(n)=isprime(23*n^2-9) \\ Charles R Greathouse IV, Jun 12 2017

Crossrefs

Sequence in context: A265835 A185074 A000216 * A051861 A296297 A290265

Adjacent sequences: A110995 A110996 A110997 * A110999 A111000 A111001

Keyword

nonn,easy

Author

Parthasarathy Nambi, Sep 30 2005

Extensions

More terms from Stefan Steinerberger, Feb 28 2006

Status

approved