

A125244


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


5



1, 7, 17, 22, 43, 343, 381, 461, 543, 923, 1045, 1182, 1486, 1839, 5643, 8260, 9009, 10947, 11793, 15915, 25151
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OFFSET

1,2


COMMENTS

a(22) > 50000.  Robert Price, May 13 2019


LINKS

Table of n, a(n) for n=1..21.


MATHEMATICA

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


CROSSREFS

Cf. A125245 = 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: A053746 A327830 A144695 * A070416 A087168 A247560
Adjacent sequences: A125241 A125242 A125243 * A125245 A125246 A125247


KEYWORD

hard,more,nonn


AUTHOR

Alexander Adamchuk, Nov 25 2006


EXTENSIONS

More terms from Ryan Propper, Mar 28 2007
a(18)a(21) from Robert Price, May 13 2019


STATUS

approved



