A120227 Numbers n such that a+n and a*n+1 are prime, case a=5.

2, 6, 8, 12, 14, 26, 36, 38, 42, 48, 54, 56, 62, 66, 84, 92, 98, 104, 108, 126, 132, 152, 162, 176, 188, 194, 206, 218, 234, 236, 246, 258, 264, 272, 276, 302, 306, 344, 348, 362, 374, 416, 426, 428, 444, 456, 462, 474, 482, 504, 518, 542, 558, 572, 594, 602

Offset

1,1

Comments

This sequence is infinite under Dickson's conjecture. - Charles R Greathouse IV, Apr 16 2012

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Reap[Do[Do[If[PrimeQ[{n+x, n*x+1}]=={True, True}, Sow[x]], {x, 2, 1000, 2}], {n, 5, 5}]][[2, 1]]
Select[Range[700], And@@PrimeQ[{#+5, 5#+1}]&] (* Harvey P. Dale, Dec 18 2011 *)

Crossrefs

Case a=4 A120226.

Cf. A092945, A106057 A085063, A120223, A120224, A120225.

Sequence in context: A102166 A024894 A153880 * A276154 A328770 A138626

Adjacent sequences: A120224 A120225 A120226 * A120228 A120229 A120230

Keyword

nonn

Author

Zak Seidov, Jun 10 2006

Status

approved