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A057196 Numbers n such that 2^n + 9 is prime. 19
1, 2, 3, 5, 6, 7, 9, 10, 18, 23, 30, 37, 47, 57, 66, 82, 95, 119, 175, 263, 295, 317, 319, 327, 670, 697, 886, 1342, 1717, 1855, 2394, 2710, 3229, 3253, 3749, 4375, 4494, 4557, 5278, 5567, 9327, 10129, 12727, 13615, 14893, 16473, 23639, 40053, 44399, 50335, 80949 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Some of the larger terms are only probable primes.

For these numbers n, 2^(n-1)*(2^n+9) has deficiency 10, cf. A101223. - M. F. Hasler, Jul 18 2016

LINKS

Robert Price, Table of n, a(n) for n = 1..56

Keith Conrad, Square patterns and infinitude of primes, University of Connecticut, 2019.

H. Lifchitz & R. Lifchitz (Editors), PRP Top Records, of the form 2^n+9.

MATHEMATICA

Do[ If[ PrimeQ[ 2^n +9 ], Print[n]], { n, 1, 15000 }]

PROG

(PARI) for(n=1, 9e9, ispseudoprime(2^n+9)&&print1(n", ")) \\ M. F. Hasler, Jul 18 2016

CROSSREFS

Cf. A104070 (primes of the form 2^n+3^2). [Klaus Brockhaus, Mar 14 2009]

Cf. A059242, A057732, A019434, A057195, A057197. [M. F. Hasler, Jul 18 2016]

Sequence in context: A344281 A171886 A018559 * A080637 A124134 A007071

Adjacent sequences:  A057193 A057194 A057195 * A057197 A057198 A057199

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Sep 15 2000

EXTENSIONS

More terms from Mike Oakes, Aug 17 2001

Edited by T. D. Noe, Oct 30 2008

STATUS

approved

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Last modified May 18 19:58 EDT 2021. Contains 344002 sequences. (Running on oeis4.)