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A085793
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Numbers n such that (n-1)*binomial(2n,n) + 1 is prime.
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2
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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
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..52.
Ed Pegg Jr, Binomial Primes.
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EXAMPLE
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9999 * 20000!/(10000!)^2 + 1 is prime
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MATHEMATICA
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Do[If[PrimeQ[(a - 1)Binomial[2 a, a] + 1], a >>> "C:\prime.txt"], {a, 1, 30000}]
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PROG
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(PARI) is(n)=ispseudoprime((n-1)*binomial(2*n, n)+1) \\ Charles R Greathouse IV, May 22 2017
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CROSSREFS
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Cf. A066699, A066726.
Sequence in context: A322853 A322801 A322798 * A281809 A143286 A160339
Adjacent sequences: A085790 A085791 A085792 * A085794 A085795 A085796
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KEYWORD
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nonn
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AUTHOR
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Ed Pegg Jr, Jul 23 2003
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STATUS
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approved
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