

A162021


Triplesafe primes which are also tripleSophie Germain primes.


0



8981279, 17313839, 18635759, 82062479, 82479119, 98517599, 112242479, 113164319, 152799359, 184829279, 193409039, 230749199, 296709839, 305598719, 339116159, 393280799, 406283519
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OFFSET

1,1


COMMENTS

The intersection of the primes in A157358 and those in A023272: they remain prime after each
of three successive applications of the substitution p>(p1)/2, and remain prime after each
three successive applications of the substitution p>2p+1. Therefore the sequence is a subsequence
of A162019.
They appear for example in the middle of chains started in A059767 or in even longer Cunningham chains. [R. J. Mathar, Jun 26 2009].


LINKS

Table of n, a(n) for n=1..17.


MATHEMATICA

f[n_]:=Module[{x}, If[PrimeQ[(n1)/2]&&PrimeQ[(((n1)/2)1)/2]&&PrimeQ[(((((n1)/ 2)1)/2)1)/2]&&PrimeQ[2*n+1]&&PrimeQ[2*(2*n+1)+1]&&PrimeQ[2*(2*(2*n+1)+1)+1], x=1, x=0]; x]; lst={}; Do[p=Prime[n]; If[f[p]!=0, AppendTo[lst, p]], {n, 6*10!}]; lst


CROSSREFS

Sequence in context: A251157 A337963 A234192 * A157815 A157821 A106787
Adjacent sequences: A162018 A162019 A162020 * A162022 A162023 A162024


KEYWORD

nonn


AUTHOR

Vladimir Joseph Stephan Orlovsky, Jun 25 2009


EXTENSIONS

Edited by R. J. Mathar, Jun 26 2009


STATUS

approved



