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 A050593 Numbers k such that 135*2^k-1 is prime. 0

%I

%S 1,9,10,13,16,21,24,34,54,153,177,184,226,238,286,334,586,618,870,

%T 3151,3397,4987,5160,14737,15309,15319,16870,29430,39298,40117,56443,

%U 58449,77845,105870,127405,170613,183373,235315,245754

%N Numbers k such that 135*2^k-1 is prime.

%H Ray Ballinger and Wilfrid Keller, <a href="http://www.prothsearch.com/riesel1.html">List of primes k.2^n + 1 for k < 300</a>

%H Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k.2^n - 1 for k < 300</a>

%H <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime</a>

%t Select[Range[1000], PrimeQ[135*2^# - 1] & ] (* _Robert Price_, Dec 23 2018 *)

%o (PARI) is(n)=ispseudoprime(135*2^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K hard,nonn,more

%O 1,2

%A _N. J. A. Sloane_, Dec 29 1999

%E a(27)-a(39) from the Wilfrid Keller link by _Robert Price_, Dec 23 2018

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Last modified September 20 04:18 EDT 2020. Contains 337264 sequences. (Running on oeis4.)