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 A066699 Numbers n such that binomial(2n,n)+1 is prime. 15
 1, 2, 4, 7, 12, 19, 22, 38, 46, 62, 68, 72, 84, 166, 184, 214, 340, 348, 445, 517, 692, 817, 1316, 1381, 2554, 2713, 5261, 6209, 6735, 7920, 8207, 8772, 9530, 13075, 13302, 13405, 15002, 16371, 19346, 24151, 26555, 28188, 29235, 33536 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(45) > 40000. All the primes corresponding to terms up to a(44) have been certified by the PFGW software performing the Brillhart-Lehmer-Selfridge N-1 test. - Giovanni Resta, Apr 05 2017 REFERENCES Aigner and Ziegler. Proofs from the Book, 2nd edition. Springer-Verlag, 2001. LINKS EXAMPLE C(4,2) + 1 = 7, a prime; so 2 is a term of the sequence. MATHEMATICA Do[If[PrimeQ[Binomial[2 a, a]+1], a >>>"C:\prime.txt"], {a, 1, 20000}] (* Ed Pegg Jr *) Select[Range[1, 5 * 10^2], PrimeQ[Binomial[2* #, # ] + 1] &] PROG (PARI) is(n)=isprime(binomial(2n, n)+1) \\ Charles R Greathouse IV, May 15 2013 CROSSREFS Cf. A085793, A066726. Sequence in context: A105807 A209616 A192521 * A188425 A087149 A090853 Adjacent sequences:  A066696 A066697 A066698 * A066700 A066701 A066702 KEYWORD nonn AUTHOR Joseph L. Pe, Jan 14 2002 EXTENSIONS More terms (not certified primes) from Jason Earls and Robert G. Wilson v, Jan 15 2002 More terms from Ed Pegg Jr, Sep 10 2003 a(40)-a(44) from Giovanni Resta, Apr 05 2017 STATUS approved

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Last modified June 25 07:13 EDT 2022. Contains 354835 sequences. (Running on oeis4.)