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A057912 Numbers k such that 3*2^k - 5 is prime. 1
2, 3, 4, 7, 9, 10, 13, 15, 25, 31, 34, 48, 52, 64, 109, 145, 162, 204, 207, 231, 271, 348, 444, 553, 559, 1504, 1708, 3048, 3970, 4423, 4668, 5737, 5877, 6130, 8584, 10663, 12517, 16591, 18450, 19362, 22291, 34468, 36637 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(44) > 44233. - Jinyuan Wang, Feb 02 2020

LINKS

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

MATHEMATICA

Do[ If[ PrimeQ[ 3*2^n - 5 ], Print[ n ] ], {n, 1, 3000} ]

PROG

(PARI) is(n)=ispseudoprime(3*2^n-5) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A057913 (3*2^k + 5 is prime).

Cf. A048488 (3*2^k - 5, but with different offset).

Sequence in context: A050029 A137451 A325091 * A141748 A057267 A277066

Adjacent sequences:  A057909 A057910 A057911 * A057913 A057914 A057915

KEYWORD

nonn,more

AUTHOR

Robert G. Wilson v, Nov 16 2000

EXTENSIONS

a(36)-a(41) from Vincenzo Librandi, Oct 10 2013

a(42)-a(43) from Jinyuan Wang, Feb 02 2020

STATUS

approved

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Last modified June 12 16:18 EDT 2021. Contains 344959 sequences. (Running on oeis4.)