A124017 Numbers n for which 2n-1, 4n-1, 8n-1, 16n-1 and 32n-1 are primes.

45, 90, 26820, 26925, 30705, 31710, 33375, 63420, 63570, 71805, 83865, 93075, 103185, 127140, 134025, 148050, 170460, 202635, 211035, 223305, 269505, 297225, 303660, 329175, 335625, 362505, 387975, 405270, 405405, 406425, 409755, 463335

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Select[15*Range[40000], And @@ PrimeQ /@ ({2, 4, 8, 16, 32}*# - 1) &] (* Ray Chandler, Nov 22 2006 *)
Select[15*Range[31000], AllTrue[#*2^Range[5]-1, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Aug 05 2019 *)

Crossrefs

Cf. A006254, A124485, A124493, A124494, A125113, A124514, A124515, A124516.

Sequence in context: A115827 A070002 A101794 * A121925 A044183 A044564

Adjacent sequences: A124014 A124015 A124016 * A124018 A124019 A124020

Keyword

nonn

Author

Artur Jasinski, Nov 04 2006

Status

approved