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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

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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

URL: https://oeis.org/A125113

⇱ A125113 - OEIS