A110912 Numbers k such that abs(23*k^2 - 36) is prime.

1, 7, 13, 31, 43, 55, 97, 101, 113, 119, 133, 139, 151, 161, 167, 185, 199, 211, 221, 227, 239, 265, 277, 283, 295, 305, 323, 353, 371, 385, 403, 407, 427, 451, 461, 463, 475, 515, 517, 539, 557, 559, 581, 613, 617, 641, 661, 685, 689, 697, 713, 767, 769, 773

Offset

1,2

Links

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

Example

If k=133 then abs(23*k^2 - 36) = 406811 is prime, so 133 is a term.

Mathematica

Select[Range[800], PrimeQ[23*#^2 - 36] &] (* Stefan Steinerberger, Feb 28 2006 *)

Prog

(Magma) [n: n in [0..1000]| IsPrime(23*n^2 - 36)]; // Vincenzo Librandi, Feb 03 2011
(PARI) is(n)=isprime(abs(23*n^2-36)); \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A283937 A231626 A343302 * A240680 A308851 A298027

Adjacent sequences: A110909 A110910 A110911 * A110913 A110914 A110915

Keyword

nonn,easy

Author

Parthasarathy Nambi, Oct 03 2005

Extensions

More terms from Stefan Steinerberger, Feb 28 2006

Definition corrected by Georg Fischer, Nov 19 2025

Status

approved