A085793 Numbers n such that (n-1)*binomial(2n,n) + 1 is prime.

2, 3, 4, 5, 6, 7, 9, 13, 17, 18, 22, 23, 28, 31, 48, 49, 52, 80, 99, 167, 201, 295, 372, 381, 391, 638, 653, 720, 779, 887, 1047, 1454, 1647, 1719, 2405, 3234, 3257, 3542, 3623, 3765, 3796, 4337, 4490, 5228, 6507, 8544, 9990, 10000, 12478, 13479, 15487, 17115

Offset

1,1

Links

Table of n, a(n) for n=1..52.

Ed Pegg Jr, Binomial Primes.

Example

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

Mathematica

Do[If[PrimeQ[(a - 1)Binomial[2 a, a] + 1], a >>> "C:\prime.txt"], {a, 1, 30000}]

Prog

(PARI) is(n)=ispseudoprime((n-1)*binomial(2*n, n)+1) \\ Charles R Greathouse IV, May 22 2017

Crossrefs

Cf. A066699, A066726.

Sequence in context: A322853 A322801 A322798 * A281809 A143286 A160339

Adjacent sequences: A085790 A085791 A085792 * A085794 A085795 A085796

Keyword

nonn

Author

Ed Pegg Jr, Jul 23 2003

Status

approved