A225098 Numbers k such that k^2 - 2 and 2*k^2 - 1 are both prime.

2, 3, 7, 13, 15, 21, 43, 49, 63, 69, 127, 155, 183, 211, 231, 237, 259, 265, 273, 293, 301, 323, 335, 391, 435, 441, 447, 489, 505, 573, 595, 671, 713, 715, 743, 757, 797, 811, 951, 959, 973, 979, 987, 993, 1035, 1147, 1197, 1287, 1359, 1393, 1415, 1429, 1443, 1491, 1525, 1597, 1617, 1653

Offset

1,1

Comments

Primes in the sequence: 2, 3, 7, 13, 43, 127, 211, 293, 743, 757, 797, 811, 1429,...

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

2^2 - 2 = 2 is prime and 2*2^2 - 1 = 7 is prime, so a(1) = 2.

Mathematica

Select[Range[1653], PrimeQ[#^2 - 2] && PrimeQ[2*#^2 - 1] &] (* T. D. Noe, May 10 2013 *)

Crossrefs

Intersection of A028870 and A066049.

Sequence in context: A286176 A318401 A322703 * A101739 A363450 A336378

Adjacent sequences: A225095 A225096 A225097 * A225099 A225100 A225101

Keyword

nonn

Author

Gerasimov Sergey, Apr 27 2013

Extensions

Corrected by R. J. Mathar, May 05 2013

Status

approved