A144834 Numbers n such that the two numbers n+1 and n+3 are both prime.

2, 4, 10, 16, 28, 40, 58, 70, 100, 106, 136, 148, 178, 190, 196, 226, 238, 268, 280, 310, 346, 418, 430, 460, 520, 568, 598, 616, 640, 658, 808, 820, 826, 856, 880, 1018, 1030, 1048, 1060, 1090, 1150, 1228, 1276, 1288, 1300, 1318, 1426, 1450, 1480, 1486, 1606

Offset: 1

Author

Giovanni Teofilatto, Sep 22 2008

Keywords

• easy
• nonn

Comments

1 less than the lesser of each twin prime pair. [Harvey P. Dale, Nov 08 2011]

Links

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

Crossrefs

Cf. A053319 (first differences).

Programs

Mathematica

Transpose[Select[Partition[Prime[Range[300]],2,1],Last[#]-First[#] == 2&]][[1]]-1 (* Harvey P. Dale, Nov 08 2011 *)

Formula

a(n) = A014574(n)-2 = A001359(n)-1. - R. J. Mathar, Sep 24 2008

Extensions

Definition edited and extended by R. J. Mathar, Sep 24 2008