A125113 Numbers n such that 2n-1, 4n-1, 8n-1, 16n-1, 32n-1 and 64n-1 are primes.

45, 31710, 63570, 202635, 405405, 534600, 561330, 589305, 666945, 799350, 903045, 979125, 1082115, 1122660, 1164735, 1303035, 1424475, 1620645, 1669995, 1892100, 1981020, 2044440, 2164230, 2222415, 2329470, 2332125, 2447445, 2448855

Offset

1,1

Links

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

Mathematica

Select[15*Range[200000], And @@ PrimeQ /@ ({2, 4, 8, 16, 32, 64}*# - 1) &] (* Ray Chandler, Nov 22 2006 *)
Select[15*Range[164000], AllTrue[# 2^Range[6]-1, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jan 20 2020 *)

Crossrefs

Cf. A006254, A124485, A124493, A124494, A124017, A124514, A124515, A124516.

Sequence in context: A007537 A287434 A225991 * A354362 A003739 A300198

Adjacent sequences: A125110 A125111 A125112 * A125114 A125115 A125116

Keyword

nonn

Author

Artur Jasinski, Nov 22 2006

Extensions

Extended by Ray Chandler, Nov 22 2006

Status

approved