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A087577 Smallest number k such that k^n + 3 is a prime. 1
2, 2, 2, 2, 8, 2, 2, 4, 4, 8, 10, 2, 20, 4, 2, 2, 10, 2, 124, 46, 16, 20, 190, 14, 68, 50, 152, 2, 34, 2, 34, 122, 130, 208, 374, 46, 68, 64, 10, 28, 248, 4, 106, 230, 34, 208, 52, 34, 154, 230, 116, 302, 656, 38, 2, 10, 16, 34, 140, 140, 20, 232, 140, 28, 64, 328, 2, 98, 28, 818 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
a(5) = 8 as 8^5 + 3= 32771 is prime, while 2^5 +3, 4^5+3 and 6^5 +3 are composite.
MATHEMATICA
snk[n_]:=Module[{k=1}, While[!PrimeQ[k^n+3], k++]; k]; Array[snk, 70] (* Harvey P. Dale, Mar 08 2014 *)
PROG
(PARI) for(j=1, 50, for (i=1, 150, if(isprime(i^j+3), print1(i, ", "); break())))
CROSSREFS
Cf. A087576.
Sequence in context: A295557 A327641 A066874 * A323741 A168281 A203610
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 17 2003
EXTENSIONS
More terms from Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 14 2004
More terms from David Wasserman, Jun 08 2005
STATUS
approved

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Last modified July 19 01:31 EDT 2024. Contains 374388 sequences. (Running on oeis4.)