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Numbers k such that 159*2^k + 1 is prime.
1

%I #38 Sep 08 2022 08:44:51

%S 6,7,9,18,19,22,30,34,42,106,190,262,339,354,379,478,523,690,718,855,

%T 963,1087,2478,3309,3862,4155,5098,6678,12898,14226,14274,18738,20065,

%U 24390,44079,103417,108850,112374,142462,280438,514927,650934,689437,1579426

%N Numbers k such that 159*2^k + 1 is prime.

%C The subsequence of prime values starts 7, 19, 379, 523, 1087, ... - _Muniru A Asiru_, Apr 28 2019

%H Jeppe Stig Nielsen, <a href="/A032456/b032456.txt">Table of n, a(n) for n = 1..45</a>

%H Ray Ballinger, <a href="http://www.prothsearch.com/index.html">Proth Search Page</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 <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>

%p select(k->isprime(159*2^k+1),[$0..1000]); # _Muniru A Asiru_, Dec 21 2018

%t Select[Range[1000], PrimeQ[159*2^# + 1] & ] (* _Robert Price_, Dec 18 2018 *)

%o (PARI) is(n)=ispseudoprime(159*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%o (Magma) [n: n in [1..1000] | IsPrime(159*2^n+1)]; // _G. C. Greubel_, Apr 28 2019

%o (Sage) [n for n in (1..1000) if is_prime(159*2^n+1)] # _G. C. Greubel_, Apr 28 2019

%o (GAP) Filtered([1..1000], k-> IsPrime(159*2^k+1)); # _G. C. Greubel_, Apr 28 2019

%K nonn,hard

%O 1,1

%A _N. J. A. Sloane_

%E a(36)-a(44) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 18 2018