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A081259 a(n) is the smallest k such that C(3n,n) divides k!. 1
2, 5, 7, 11, 13, 17, 19, 23, 23, 29, 31, 31, 37, 41, 43, 47, 47, 53, 53, 59, 61, 61, 67, 71, 73, 73, 79, 83, 83, 89, 89, 89, 97, 101, 103, 107, 109, 113, 113, 113, 113, 113, 127, 131, 131, 137, 139, 139, 139, 149, 151, 151, 157, 157, 163, 167, 167, 173, 173, 179, 181 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is the largest prime < 3n. More generally the smallest k such that C(mn,n) divides k! is the largest prime < mn.

LINKS

Table of n, a(n) for n=1..61.

FORMULA

a(n) = A151799(3n). - R. J. Mathar, Jul 18 2015

MATHEMATICA

NextPrime[3Range[70], -1] (* Harvey P. Dale, Oct 20 2011 *)

PROG

(PARI) a(n)=if(n<0, 0, s=1; while(k!%binomial(3*n, n)>0, k++); k)

CROSSREFS

Cf. A060308, A151799.

Sequence in context: A229470 A157829 A020581 * A177512 A118751 A173494

Adjacent sequences:  A081256 A081257 A081258 * A081260 A081261 A081262

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Apr 20 2003

STATUS

approved

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Last modified November 18 04:44 EST 2019. Contains 329248 sequences. (Running on oeis4.)