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

Author

Benoit Cloitre, Feb 23 2002

Keywords

• easy
• nonn

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

Crossrefs

Cf. A005574, A002384.

Programs

Magma

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

Mathematica

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