

A219039


Numbers n such that 3^n  16 is prime.


16



3, 5, 11, 15, 51, 69, 99, 227, 381, 537, 9135, 9737, 58437, 105567, 121779, 123645
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OFFSET

1,1


COMMENTS

a(17) > 2*10^5.  Robert Price, Sep 29 2013


LINKS

Table of n, a(n) for n=1..16.


EXAMPLE

For n=3, a(3)=3^316=11 and 11 is prime. Hence n=3 is included in the sequence.


MATHEMATICA

Do[If[PrimeQ[3^n  16], Print[n]], {n, 1, 10000}]


PROG

(PARI) is(n)=isprime(3^n16) \\ Charles R Greathouse IV, Feb 17 2017


CROSSREFS

Cf. Sequences of numbers n such that 3^n + m is prime:
(m = 2) A051783, (m = 2) A014224, (m = 4) A058958, (m = 4) A058959,
(m = 8) A217136, (m = 8) A217135, (m = 10) A217137, (m = 10) A217347,
(m = 14) A219035, (m = 14) A219038, (m = 16) A205647, (m = 16) this sequence, (m = 20) A219040, (m = 20) A219041.
Note that if m is a multiple of 3, 3^n + m is also a multiple of 3 (for n greater than 0), and as such isn't prime.
Sequence in context: A318915 A322439 A018313 * A074820 A327043 A006169
Adjacent sequences: A219036 A219037 A219038 * A219040 A219041 A219042


KEYWORD

nonn


AUTHOR

Nicolas M. Perrault, Nov 10 2012


EXTENSIONS

a(13)a(16) from Robert Price, Sep 29 2013


STATUS

approved



