

A066726


Numbers n such that binomial(2n, n)  1 is prime.


16



2, 3, 5, 9, 15, 29, 43, 51, 113, 184, 213, 222, 267, 279, 369, 402, 441, 603, 812, 839, 902, 1422, 1542, 1824, 2983, 3065, 3911, 3958, 4192, 4587, 4865, 5543, 5837, 7902, 9299, 9722, 10412, 10648, 11498, 12803, 14428, 15876, 20173, 26311
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OFFSET

1,1


COMMENTS

I.e., numbers n such that (2*n)!/(n!)^21 is prime.  Hugo Pfoertner, Sep 25 2005
The next term is > 30000.  Vaclav Kotesovec, May 03 2021


LINKS

Table of n, a(n) for n=1..44.


MATHEMATICA

Do[ If[ PrimeQ[ Binomial[2n, n]  1], Print[n]], {n, 1, 2000} ]


PROG

(PARI) is(n)=isprime(binomial(2*n, n)1) \\ Charles R Greathouse IV, Feb 17 2017


CROSSREFS

Cf. A066699, A085793.
Cf. A092751 = primes of the form (2*n)!/(n!)^21, A112853 = (2*n)!/n!1 is prime, A112855 = (2*n)!/n!+1 is prime, A066699 = (2*n)!/(n!)^2+1 is prime, A112861 = (2*n)!/(2*(n!)^2)1 is prime, A112863 = (2*n)!/(2*(n!)^2)+1 is prime.  Hugo Pfoertner, Sep 25 2005
Sequence in context: A092424 A167510 A191701 * A124642 A269153 A232866
Adjacent sequences: A066723 A066724 A066725 * A066727 A066728 A066729


KEYWORD

nonn


AUTHOR

Robert G. Wilson v, Jan 15 2002


EXTENSIONS

More terms from Ed Pegg Jr, Sep 10 2003
Edited by N. J. A. Sloane, Aug 23 2008 at the suggestion of R. J. Mathar
a(43)a(44) from Vaclav Kotesovec, May 03 2021


STATUS

approved



