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A057910 Numbers k such that 2*3^k - 5 is prime. 1
2, 4, 6, 10, 12, 13, 19, 43, 48, 64, 72, 97, 187, 190, 336, 348, 676, 2484, 2719, 3298, 4726, 9901, 24466 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(24) > 37734. - Jinyuan Wang, Jan 20 2020

LINKS

Table of n, a(n) for n=1..23.

MATHEMATICA

Do[ If[ PrimeQ[ 2*3^n - 5 ], Print[ n ] ], {n, 1, 2500} ]

Select[Range[10000], PrimeQ[2*3^#-5]&] (* Harvey P. Dale, Jan 19 2018 *)

PROG

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

CROSSREFS

Cf. A057911 (2*3^k + 5 is prime).

Sequence in context: A309374 A226295 A090127 * A336066 A120351 A022305

Adjacent sequences:  A057907 A057908 A057909 * A057911 A057912 A057913

KEYWORD

nonn,more

AUTHOR

Robert G. Wilson v, Nov 16 2000

EXTENSIONS

a(23) from Jinyuan Wang, Jan 20 2020

STATUS

approved

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Last modified June 21 19:59 EDT 2021. Contains 345365 sequences. (Running on oeis4.)