A058603 Numbers n such that 7*3^n + 2 is prime.

1, 3, 4, 31, 33, 76, 196, 319, 405, 591, 2028, 2140, 4039, 5745, 16629, 18061, 20265, 54129, 119712

Offset

1,2

Comments

a(20) > 2*10^5. - Robert Price, May 12 2015

Links

Table of n, a(n) for n=1..19.

Mathematica

Do[ If[ PrimeQ[ 7*3^n + 2 ], Print[ n ] ], {n, 1, 2500} ]
Select[Range[0, 10000], PrimeQ[(7*3^# + 2)] &] (* Vincenzo Librandi, Sep 29 2012 *)

Prog

(PARI) is(n)=ispseudoprime(7*3^n+2) \\ Charles R Greathouse IV, Jun 12 2017

Crossrefs

Sequence in context: A347978 A127068 A372794 * A042653 A219679 A042431

Adjacent sequences: A058600 A058601 A058602 * A058604 A058605 A058606

Keyword

nonn

Author

Robert G. Wilson v, Dec 26 2000

Extensions

a(13)-a(14) from Vincenzo Librandi, Sep 29 2012

a(15)-a(19) from Robert Price, May 12 2015

Status

approved