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A050590 Numbers k such that 129*2^k-1 is prime. 0

%I #25 Jan 17 2019 10:08:17

%S 1,3,4,5,8,9,12,16,28,51,56,59,72,73,88,93,105,148,165,292,368,445,

%T 635,771,773,940,1173,1965,2661,3092,5001,5091,8741,9773,13960,15328,

%U 19408,19911,21228,34876,37341,38564,39055,39152,45395,68825,72360,78365,126303,130240,150808,214985

%N Numbers k such that 129*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 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[129*2^# - 1] & ] (* _Robert Price_, Dec 23 2018 *)

%o (PARI) is(n)=ispseudoprime(129*2^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K hard,nonn

%O 1,2

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

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

%E a(49)-a(52) from the Wilfrid Keller link by _Robert Price_, Dec 23 2018

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)