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A209120 Numbers n such that (33^n - 1)/32 is prime. 1
3, 197, 3581, 6871, 183661 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..5.

H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.

H. Lifchitz, Mersenne and Fermat primes field

Index to primes in various ranges, form ((k+1)^n-1)/k

MATHEMATICA

Select[Prime[Range[100]], PrimeQ[(33^#-1)/32]&]

PROG

(PARI) isok(n) = isprime((33^n-1)/32); \\ Michel Marcus, Mar 13 2016

CROSSREFS

Sequence in context: A101382 A000724 A309749 * A256407 A256406 A157565

Adjacent sequences:  A209117 A209118 A209119 * A209121 A209122 A209123

KEYWORD

hard,more,nonn

AUTHOR

Robert Price, Mar 05 2012

EXTENSIONS

a(5) corresponds to a probable prime discovered by Paul Bourdelais, Dec 31 2018

STATUS

approved

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Last modified July 13 05:18 EDT 2020. Contains 335673 sequences. (Running on oeis4.)