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A057220 Numbers n such that 2^n - 23 is prime. 0
2, 4, 6, 8, 12, 14, 18, 36, 68, 152, 212, 324, 1434, 1592, 1668, 3338, 7908, 9662 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Note that for the values 2 and 4 the primes are negative.

LINKS

Table of n, a(n) for n=1..18.

MATHEMATICA

Do[ If[ PrimeQ[ 2^n - 23 ], Print[ n ] ], { n, 1, 15000} ]

PROG

(PARI) is(n)=ispseudoprime(2^n-23) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A227308 A214294 A233578 * A294847 A082742 A131197

Adjacent sequences:  A057217 A057218 A057219 * A057221 A057222 A057223

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Sep 16 2000

STATUS

approved

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Last modified July 20 01:17 EDT 2019. Contains 325168 sequences. (Running on oeis4.)