A050834 - OEIS

%I #22 Jan 17 2019 10:08:17

%S 2,3,5,6,8,11,12,15,18,23,27,36,39,44,45,56,59,63,81,84,150,188,264,

%T 275,282,299,321,338,390,552,657,722,930,1139,1388,1491,1625,2196,

%U 2519,2541,2736,2766,3630,4202,4875,5643,6150,10134,20328,20805,22902,25770,30918

%N Numbers k such that 165*2^k-1 is prime.

%H Robert Price, <a href="/A050834/b050834.txt">Table of n, a(n) for n = 1..74</a>

%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 Kosmaj, <a href="http://www.15k.org/riesellist.html">Riesel list 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[165*2^# - 1] & ] (* _Robert Price_, Dec 29 2018 *)

%o (PARI) is(n)=ispseudoprime(165*2^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K hard,nonn

%O 1,1

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

%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

%E a(54)-a(74) from the Wilfrid Keller link by _Robert Price_, Dec 29 2018