This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS I.e., numbers n such that (2*n)!/(n!)^2-1 is prime. - Hugo Pfoertner, Sep 25 2005 LINKS 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!)^2-1, A112853 = (2*n)!/n!-1 is prime, A112855 = (2*n)!/n!+1 is prime, A112859 = (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 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 17 18:47 EDT 2019. Contains 325109 sequences. (Running on oeis4.)