A130176 Numbers n with property that the largest prime factor is a Sophie Germain prime.

2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 16, 18, 20, 22, 23, 24, 25, 27, 29, 30, 32, 33, 36, 40, 41, 44, 45, 46, 48, 50, 53, 54, 55, 58, 60, 64, 66, 69, 72, 75, 77, 80, 81, 82, 83, 87, 88, 89, 90, 92, 96, 99, 100, 106, 108, 110, 113, 115, 116, 120, 121, 123, 125, 128, 131, 132

Offset: 1

Author

Zak Seidov, May 14 2007

Keywords

• nonn

Comments

Prime terms 2,3,5,11,23,29,... are in A005384.

A156541 is a subsequence. [Reinhard Zumkeller, Feb 10 2009]

A156660(A006530(a(n))) = 1. [Reinhard Zumkeller, Dec 03 2009]

Crossrefs

Cf. A005384.

Programs

Mathematica

Select[Range[2, 132], PrimeQ[FactorInteger[#][[-1, 1]]*2 + 1] &] (* Ivan Neretin, Aug 30 2015 *)