A067664 Numbers n such that n^2 + 1 and n^2 + n + 1 are primes.

1, 2, 6, 14, 20, 24, 54, 66, 90, 110, 150, 176, 206, 236, 314, 584, 644, 686, 696, 860, 864, 890, 920, 950, 960, 1070, 1146, 1274, 1314, 1340, 1434, 1440, 1494, 1566, 1616, 1644, 1676, 1700, 1716, 1970, 1974, 2054, 2064, 2136, 2360, 2430, 2456, 2604, 2646

Offset

1,2

Comments

All the terms are even numbers except for a(1) = 1. - Metin Sariyar, Nov 23 2019

Links

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

Mathematica

Join[{1}, Select[Range[2, 10^6, 2], PrimeQ[#^2+1]&&PrimeQ[#^2+#+1]&]] (* Metin Sariyar, Nov 23 2019 *)

Prog

(Magma) [n: n in [0..10000]| IsPrime(n^2+1) and IsPrime(n^2+n+1)] // Vincenzo Librandi, Aug 07 2010

Crossrefs

Cf. A005574, A002384.

Sequence in context: A308394 A246068 A032643 * A130800 A067262 A107369

Adjacent sequences: A067661 A067662 A067663 * A067665 A067666 A067667

Keyword

easy,nonn

Author

Benoit Cloitre, Feb 23 2002

Status

approved