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A108320 Numbers n such that 609 * 10^n - 1 is prime. 0
1, 2, 3, 4, 5, 6, 12, 17, 43, 46, 50, 88, 110, 187, 472, 832, 834, 1034, 1311, 1700, 2756, 5470, 6124, 7404, 7891, 12010 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..26.

EXAMPLE

a(4)=4 because 609*10^4-1 = 6089999, a prime.

PROG

(PARI) is(n)=ispseudoprime(609*10^n-1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A053580.

Sequence in context: A032885 A023788 A032989 * A177958 A032941 A273733

Adjacent sequences:  A108317 A108318 A108319 * A108321 A108322 A108323

KEYWORD

more,nonn

AUTHOR

Jason Earls, Jun 30 2005

STATUS

approved

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Last modified December 14 11:52 EST 2018. Contains 318097 sequences. (Running on oeis4.)