

A057328


First member of a prime 5tuple in a 2p1 progression.


14



1531, 6841, 15391, 16651, 33301, 44371, 57991, 66601, 83431, 105871, 145021, 150151, 165901, 199621, 209431, 212851, 231241, 242551, 291271, 319681, 331801, 346141, 377491, 381631, 385591, 445741, 451411, 478801, 481021, 506791, 507781
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OFFSET

1,1


COMMENTS

Numbers n such that n remains prime through 4 iterations of function f(x) = 2x  1.


LINKS



EXAMPLE

Quintuplets are (1531, 3061, 6121, 12241, 24481), (6841, 13681, 27361, 54721, 109441), ...


MATHEMATICA

pQ[n_] := And @@ PrimeQ[NestList[2 #  1 &, n, 4]]; t = {}; Do[p = Prime[n]; If[pQ[p], AppendTo[t, p]], {n, 42500}]; t (* Jayanta Basu, Jun 17 2013 *)
Select[Prime[Range[50000]], AllTrue[Rest[NestList[2#1&, #, 4]], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 30 2019 *)


PROG

(Magma) [ p: p in PrimesUpTo(6*10^5)  forall{q: k in [1..4]  IsPrime(q) where q is 2^k*(p1)+1} ]; // Bruno Berselli, Nov 23 2011


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



