

A109387


Numbers n such that 3^n  n^3 is prime.


11



1, 4, 10, 52, 112, 212, 346, 406, 512, 13904, 76610, 89746, 114892
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OFFSET

1,2


COMMENTS

Terms <= 512 correspond to certified primes. Next term after 13904 is greater than 20000.


LINKS

Table of n, a(n) for n=1..13.


EXAMPLE

a(2)=4 because 3^4 4^3 = 17 is prime
3^10  10^3 = 58049 is prime, hence 10 is a term.


MATHEMATICA

Do[If[PrimeQ[3^n  n^3], Print[n]], {n, 1, 20000}]


PROG

(PARI) is(n)=isprime(3^nn^3) \\ Charles R Greathouse IV, Feb 17 2017


CROSSREFS

Sequence in context: A151611 A208236 A032495 * A018844 A007027 A192444
Adjacent sequences: A109384 A109385 A109386 * A109388 A109389 A109390


KEYWORD

hard,more,nonn


AUTHOR

Ryan Propper, Jun 26 2005


EXTENSIONS

Two more terms from Donovan Johnson, Feb 26 2008
a(13) from Norbert Schneider submitted by Robert Price, Mar 16 2019


STATUS

approved



