A125243 Numbers k such that binomial(5k, k) + 1 is prime.

0, 22, 86, 154, 160, 488, 705, 958, 975, 1262, 1932, 2845, 12718, 14434, 20337, 38834, 40433, 44874

Offset

1,2

Comments

a(19) > 50000. - Robert Price, May 11 2019

Links

Table of n, a(n) for n=1..18.

Mathematica

Do[f=Binomial[5n, n]+1; If[PrimeQ[f], Print[n]], {n, 1, 1000}]

Crossrefs

Cf. A125242 = numbers n such that binomial(5n, 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, A125244, A125245.

Sequence in context: A235766 A044209 A044590 * A298443 A197720 A195323

Adjacent sequences: A125240 A125241 A125242 * A125244 A125245 A125246

Keyword

hard,more,nonn

Author

Alexander Adamchuk, Nov 25 2006

Extensions

More terms from Ryan Propper, Jan 05 2007

a(1)=0 prepended and a(13)-a(18) added by Robert Price, May 11 2019

Status

approved