A131530 Numbers k such that k^2 - k - 1 and k^2 - k + 1 are twin primes.

3, 4, 6, 7, 9, 16, 21, 22, 25, 39, 42, 51, 55, 60, 67, 90, 102, 132, 139, 142, 154, 156, 165, 177, 189, 204, 207, 210, 216, 219, 232, 237, 247, 289, 291, 310, 315, 352, 379, 396, 406, 454, 456, 457, 496, 501, 519, 531, 552, 561, 625, 645, 669, 687, 721, 729, 744

Offset: 1

Author

Pierre CAMI, Aug 26 2007

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..5000

Crossrefs

Intersection of A002328 and A055494. - Michel Marcus, Jan 24 2018

Programs

Magma

[n: n in [0..500] | IsPrime(n^2-n-1) and IsPrime(n^2-n+1)]; // Vincenzo Librandi, Nov 23 2010

Mathematica

Select[Range[744],AllTrue[{#^2-#-1,#^2-#+1},PrimeQ]&] (* James C. McMahon, Feb 25 2025 *)