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A057915 Numbers k such that 2*5^k - 3 is prime. 0
1, 2, 5, 6, 8, 9, 17, 76, 154, 188, 329, 497, 609, 1401, 2320, 3250, 3281, 5489, 6868, 7602 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(21) > 22802. - Jinyuan Wang, Dec 14 2019

LINKS

Table of n, a(n) for n=1..20.

MATHEMATICA

Do[ If[ PrimeQ[ 2*5^n - 3 ], Print[ n ] ], {n, 1, 2000} ]

PROG

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

CROSSREFS

Cf. A057914 (2*5^k + 3 is prime).

Sequence in context: A102611 A323112 A176114 * A154329 A176590 A253061

Adjacent sequences:  A057912 A057913 A057914 * A057916 A057917 A057918

KEYWORD

nonn,more

AUTHOR

Robert G. Wilson v, Nov 16 2000

EXTENSIONS

a(18)-a(20) from Jinyuan Wang, Dec 14 2019

STATUS

approved

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Last modified June 15 21:38 EDT 2021. Contains 345052 sequences. (Running on oeis4.)