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A085793 Numbers n such that (n-1)*binomial(2n,n) + 1 is prime. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 29 10:08 EDT 2022. Contains 354912 sequences. (Running on oeis4.)