login
A087576
Smallest number k > 1 such that k^n+2 is prime.
6
3, 3, 3, 3, 9, 39, 9, 3, 11, 3, 15, 9, 9, 3, 3, 15, 5, 9, 63, 15, 27, 39, 41, 3, 51, 3, 59, 75, 119, 99, 71, 141, 209, 87, 65, 3, 275, 45, 23, 21, 27, 27, 69, 477, 59, 147, 231, 1605, 9, 291, 65, 15, 75, 57, 9, 225, 119, 273, 855, 33, 77, 513, 3, 219, 75, 51, 489, 369
OFFSET
1,1
COMMENTS
Some of the results were computed using the PrimeFormGW (PFGW) primality-testing program. - Hugo Pfoertner, Nov 16 2019
LINKS
MATHEMATICA
Table[k = 2; While[p = k^n + 2; ! PrimeQ[p], k++]; k, {n, 68}] (* T. D. Noe, Apr 03 2012 *)
PROG
(PARI) for(n=1, 68, forstep(k=3, oo, 2, if(isprime(k^n+2), print1(k, ", "); break))) \\ Hugo Pfoertner, Oct 30 2018
CROSSREFS
Cf. A095302 (corresponding primes), A095303 (smallest k such that k^n-2 is prime), A095304 (corresponding primes).
Sequence in context: A375230 A111575 A161836 * A337328 A201700 A087575
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 17 2003
EXTENSIONS
Corrected and extended by Hugo Pfoertner, computed using PFGW, Jun 01 2004
a(49) corrected by T. D. Noe, Apr 03 2012
STATUS
approved