A125221 Numbers k such that binomial(3k, k) + 1 is prime.
0, 12, 43, 53, 120, 121, 184, 778, 823, 1179, 1212, 1670, 3187, 3353, 4282, 5420, 5592, 5826, 6526, 7405, 7581, 7619, 13213, 17258, 17532, 17644, 20274, 24404, 40406, 41981, 46955, 52968, 52968, 64289, 77776, 82571, 91231, 99641
Offset: 1
Programs
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Mathematica
Do[f=Binomial[3n,n]+1;If[PrimeQ[f],Print[n]],{n,1,1000}] -
PARI
is(n)=isprime(binomial(3*n,n)+1) \\ Charles R Greathouse IV, Feb 17 2017
Extensions
a(10)-a(15) from Robert G. Wilson v, Nov 26 2006
More terms from Stefan Steinerberger, Sep 07 2007
5 more terms from Ryan Propper, Jan 01 2008
a(24)-a(31) from Robert Price, Apr 17 2019
a(32)-a(38) from Robert Price, Aug 13 2024
Comments