A124514 Numbers k for which 2*k-1, 4*k-1, 8*k-1, 16*k-1, 32*k-1, 64*k-1 and 128*k-1 are primes.

561330, 1082115, 1164735, 5128905, 5154945, 6157350, 7015155, 7072770, 9549960, 11551830, 12088065, 14421825, 18544365, 19099920, 21194760, 24580050, 25392720, 26277285, 31400085, 34359030, 42932385, 44087025, 47915595

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Mathematica

Select[15*Range[3200000], And @@ PrimeQ /@ ({2, 4, 8, 16, 32, 64, 128}*# - 1) &] (* Ray Chandler, Nov 22 2006 *)
apQ[n_]:=AllTrue[NestList[2#&, 2n, 6]-1, PrimeQ]; Select[15*Range[ 32*10^5], apQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 08 2019 *)

Crossrefs

Cf. A006254, A124485, A124493, A124494, A124017, A125113, A124515, A124516.

Sequence in context: A206194 A250534 A234207 * A100416 A151878 A273236

Adjacent sequences: A124511 A124512 A124513 * A124515 A124516 A124517

Keyword

nonn

Author

Artur Jasinski, Nov 04 2006

Status

approved