A032390 - OEIS

%I #33 Dec 22 2024 20:23:48

%S 1,4,5,7,12,15,16,21,25,27,32,35,36,39,48,89,104,121,125,148,152,267,

%T 271,277,296,324,344,396,421,436,447,539,577,592,711,809,852,1384,

%U 1972,2624,2829,3497,3945,3995,4911,5225,5676,5811,7025,7671,8512,10399

%N Numbers k such that 81*2^k+1 is prime.

%H Jeppe Stig Nielsen, <a href="/A032390/b032390.txt">Table of n, a(n) for n = 1..87</a> (terms n = 1..81 from Joerg Arndt)

%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>

%o (PARI) is(n)=ispseudoprime(81*2^n+1) \\ _Charles R Greathouse IV_, Jun 07 2017

%K nonn

%O 1,2

%A _James R. Buddenhagen_