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A164523 Nonnegative numbers n such that 6*2^n-1 is prime. 0
0, 1, 2, 3, 5, 6, 10, 17, 33, 37, 42, 54, 63, 75, 93, 102, 142, 205, 215, 305, 323, 390, 457, 469, 826, 1273, 3275, 4203, 5133, 7558, 12675, 14897, 18122, 18818, 25689, 26458, 41627, 51386, 71782, 80329, 85686, 88170, 97062 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The associated primes are in A007505.

LINKS

Table of n, a(n) for n=1..43.

FORMULA

a(n) = A002235(n+1)-1. - R. J. Mathar, Aug 17 2009

EXAMPLE

n=0 is in the sequence because 6*2^0-1=5 is prime. n=1 is in the sequence because 6*2^1-1=11 is prime.

PROG

(PARI) is(n)=ispseudoprime(6*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A194358 A018727 A161715 * A227305 A240949 A033159

Adjacent sequences:  A164520 A164521 A164522 * A164524 A164525 A164526

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Aug 15 2009

EXTENSIONS

Extended by R. J. Mathar, Aug 17 2009

a(28)-a(43) from Donovan Johnson, Jul 09 2010

STATUS

approved

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Last modified June 20 10:13 EDT 2019. Contains 324234 sequences. (Running on oeis4.)