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A130176 Numbers n with property that the largest prime factor is a Sophie Germain prime. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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]

LINKS

Table of n, a(n) for n=1..67.

MATHEMATICA

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

CROSSREFS

Cf. A005384.

Sequence in context: A302540 A332487 A067942 * A156541 A325663 A277620

Adjacent sequences:  A130173 A130174 A130175 * A130177 A130178 A130179

KEYWORD

nonn

AUTHOR

Zak Seidov, May 14 2007

STATUS

approved

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Last modified May 18 13:09 EDT 2021. Contains 343995 sequences. (Running on oeis4.)