

A065854


Smallest prime q such that (p^q1)/(p1) is a prime, where p = prime(n).


6



2, 3, 3, 5, 17, 5, 3, 19, 5, 5, 7, 13, 3, 5, 127, 11, 3, 7, 19, 3, 5, 5, 5, 3, 17, 3, 19, 17, 17, 23, 5, 3, 11, 163, 7, 13, 17, 7, 3, 3, 19, 17, 17, 5, 31, 577, 41, 239, 5, 11, 113, 5, 17, 7, 23, 5
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OFFSET

1,1


COMMENTS

a(n) = 2*A065813(n) + 1, n > 1.


LINKS

Table of n, a(n) for n=1..56.
Andy Steward, Titanic Prime Generalized Repunits


MATHEMATICA

Do[p = Prime[n]; k = 1; While[ !PrimeQ[ (p^Prime[k]  1)/(p  1)], k++ ]; Print[ Prime[k]], {n, 1, 56} ]


PROG

(PARI) { allocatemem(932245000); for (n=1, 100, p=prime(n); q=2; while (!isprime((p^q  1)/(p  1)), q=nextprime(q + 1)); write("b065854.txt", n, " ", q) ) } \\ Harry J. Smith, Nov 01 2009


CROSSREFS

Cf. A084740 (least k such that (n^k1)/(n1) is prime).
Sequence in context: A275914 A154923 A154693 * A263769 A064776 A270592
Adjacent sequences: A065851 A065852 A065853 * A065855 A065856 A065857


KEYWORD

hard,nonn


AUTHOR

Vladeta Jovovic, Nov 26 2001


STATUS

approved



