A085793 - OEIS

%I #17 Sep 16 2024 03:28:24

%S 2,3,4,5,6,7,9,13,17,18,22,23,28,31,48,49,52,80,99,167,201,295,372,

%T 381,391,638,653,720,779,887,1047,1454,1647,1719,2405,3234,3257,3542,

%U 3623,3765,3796,4337,4490,5228,6507,8544,9990,10000,12478,13479,15487,17115

%N Numbers k such that (k-1)*binomial(2k,k) + 1 is prime.

%C a(69) > 10^5 - _Robert Price_, Sep 15 2024

%H Robert Price, <a href="/A085793/b085793.txt">Table of n, a(n) for n = 1..68</a>

%H Ed Pegg Jr, <a href="http://www.mathpuzzle.com/">Binomial Primes</a>.

%e 9999 * 20000!/(10000!)^2 + 1 is prime

%o (PARI) is(n)=ispseudoprime((n-1)*binomial(2*n,n)+1) \\ _Charles R Greathouse IV_, May 22 2017

%Y Cf. A066699, A066726.

%K nonn

%O 1,1

%A _Ed Pegg Jr_, Jul 23 2003

%E a(53)-a(68) from _Robert Price_, Sep 15 2024