A125245 Numbers k such that binomial(6k, k) + 1 is prime.

0, 1, 2, 4, 10, 15, 98, 111, 118, 236, 280, 512, 1284, 1303, 1818, 2525, 2692, 4620, 8405, 11539, 13190, 21525, 30338, 48069

Offset

1,3

Comments

a(25) > 50000. - Robert Price, May 13 2019

Links

Table of n, a(n) for n=1..24.

Mathematica

Do[f=Binomial[6n, n]+1; If[PrimeQ[f], Print[n]], {n, 1, 1000}]

Crossrefs

Cf. A125244 = numbers n such that binomial(6n, n) - 1 is prime. Cf. A066699 = numbers n such that binomial(2n, n) + 1 is prime. Cf. A066726 = numbers n such that binomial(2n, n) - 1 is prime. Cf. A125220, A125221, A125240, A125241, A125242, A125243.

Sequence in context: A048200 A058201 A000947 * A371896 A358317 A096689

Adjacent sequences: A125242 A125243 A125244 * A125246 A125247 A125248

Keyword

hard,more,nonn

Author

Alexander Adamchuk, Nov 25 2006

Extensions

More terms from Ryan Propper, Mar 28 2007

a(1)=0 and a(20)-a(24) from Robert Price, May 13 2019

Status

approved