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A217070

Numbers k such that (k^13-1)/(k-1) is prime.

2, 3, 5, 7, 34, 37, 43, 59, 72, 94, 98, 110, 133, 149, 151, 159, 190, 207, 219, 221, 251, 260, 264, 267, 282, 286, 291, 319, 355, 363, 373, 382, 397, 398, 402, 406, 408, 412, 436, 442, 486, 489, 507, 542, 544, 552, 553, 582, 585, 592, 603, 610, 614, 634, 643

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[2, 1000], PrimeQ[(#^13 - 1)/(# - 1)] &] (* T. D. Noe, Sep 26 2012 *)

PROG

(Magma) [n: n in [2..1000] |IsPrime((n^13 - 1) div (n - 1))]; // Vincenzo Librandi, Sep 28 2012

(PARI) is(n)=isprime(polcyclo(13, n)) \\ Charles R Greathouse IV, Apr 28 2015

CROSSREFS

Cf. A002384, A049409, A100330, A162862, A217071-A217089.