A176682 Numbers k such that k^2 +-7 are primes.

6, 12, 18, 36, 48, 60, 66, 132, 138, 162, 186, 192, 216, 228, 270, 330, 360, 366, 408, 468, 474, 582, 606, 642, 678, 708, 744, 792, 1086, 1182, 1236, 1308, 1326, 1458, 1524, 1686, 1782, 1902, 1998, 2040, 2124, 2178, 2208, 2244, 2358, 2370, 2634, 2658, 2760

Offset

1,1

Links

Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Example

12 is in the sequence, because 12^2 - 7 = 137 and 12^2 + 7 = 151 are primes.

Mathematica

Select[Range[8! ], PrimeQ[ #^2-7]&&PrimeQ[ #^2+7]&]

Crossrefs

Cf. A097698, A108701, A176681

Sequence in context: A268925 A134107 A213360 * A226640 A067143 A206038

Adjacent sequences: A176679 A176680 A176681 * A176683 A176684 A176685

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Apr 23 2010

Status

approved