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A096304 Numbers n such that 3n does not divide (6n-4)!/[(3n-2)!(3n-1)! ]. 4
1, 2, 3, 4, 5, 9, 10, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 36, 37, 38, 39, 40, 41, 81, 82, 83, 84, 85, 86, 90, 91, 92, 93, 94, 95, 108, 109, 110, 111, 112, 113, 117, 118, 119, 120, 121, 122, 243, 244, 245, 246, 247, 248, 252, 253, 254, 255, 256, 257, 270, 271 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Equivalently, members of A019469 divisible by 3, divided by 3.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..600

FORMULA

a(n) = 9 * A005836([n/6]) + (n mod 6) (conjectured).

MATHEMATICA

Select[Range[300], Mod[(6#-4)!/((3#-2)!(3#-1)!), 3#]!=0&] (* Harvey P. Dale, Jun 11 2019 *)

PROG

(PARI) for(n=1, 300, if(((6*n-4)!/(3*n-2)!/(3*n-1)!)%(3*n), print1(n", ")))

CROSSREFS

Sequence in context: A068586 A068585 A037472 * A119955 A158573 A194398

Adjacent sequences:  A096301 A096302 A096303 * A096305 A096306 A096307

KEYWORD

nonn

AUTHOR

Ralf Stephan, Aug 03 2004

STATUS

approved

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Last modified July 10 00:25 EDT 2020. Contains 335570 sequences. (Running on oeis4.)