A209120 Numbers n such that (33^n - 1)/32 is prime.

3, 197, 3581, 6871, 183661

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 * A336250 A374514 A256407

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