A032415 - OEIS

%I #38 Dec 23 2024 11:37:29

%S 1,3,9,13,19,21,25,51,55,97,153,165,199,261,285,361,373,465,475,529,

%T 765,2065,3553,4377,5421,6859,7371,11815,21657,29089,31843,33549,

%U 35017,50169,102321,114073,118321,218697,261999,278175,430231,470245,1494099,4227493

%N Numbers k such that 131*2^k+1 is prime.

%H Jeppe Stig Nielsen, <a href="/A032415/b032415.txt">Table of n, a(n) for n = 1..47</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 Y. Gallot, <a href="http://www.utm.edu/research/primes/programs/gallot/index.html">Proth.exe: Windows Program for Finding Large Primes</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[131*2^# + 1] & ] (* _Robert Price_, Dec 17 2018 *)

%o (PARI) is(n)=ispseudoprime(131*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%o (Magma) [n: n in [1..6000] | IsPrime(131*2^n+1)]; // _Vincenzo Librandi_, Dec 18 2018

%K nonn

%O 1,2

%A _James R. Buddenhagen_

%E Extended by _Hugo Pfoertner_, Jul 02 2003

%E a(38)-a(43) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 17 2018

%E a(44) from _Jeppe Stig Nielsen_, Dec 23 2024