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A125245 Numbers k such that binomial(6k, k) + 1 is prime. 5
0, 1, 2, 4, 10, 15, 98, 111, 118, 236, 280, 512, 1284, 1303, 1818, 2525, 2692, 4620, 8405, 11539, 13190, 21525, 30338, 48069 (list; graph; refs; listen; history; text; internal format)
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 * A096689 A039682 A218665

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

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Last modified October 22 18:05 EDT 2019. Contains 328319 sequences. (Running on oeis4.)