

A127427


v_3( (6n)! )  v_3( (3n)! ), where v_3(N) is the 3adic valuation A007949(N).


1



0, 1, 3, 4, 5, 8, 9, 10, 12, 13, 14, 16, 17, 18, 22, 23, 24, 26, 27, 28, 30, 31, 32, 35, 36, 37, 39, 40, 41, 43, 44, 45, 48, 49, 50, 52, 53, 54, 56, 57, 58, 63, 64, 65, 67, 68, 69, 71, 72, 73, 76, 77, 78, 80, 81, 82, 84, 85, 86, 89, 90, 91, 93, 94, 95, 97, 98, 99, 103, 104, 105, 107
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OFFSET

0,3


LINKS

Table of n, a(n) for n=0..71.
SungHyuk Cha, On Integer Sequences Derived from Balanced kary Trees, Applied Mathematics in Electrical and Computer Engineering, 2012.  From N. J. A. Sloane, Jun 12 2012
SungHyuk Cha, On Complete and Size Balanced kary Tree Integer Sequences, International Journal of Applied Mathematics and Informatics, Issue 2, Volume 6, 2012, pp. 6775.  From N. J. A. Sloane, Dec 24 2012


FORMULA

a(n)  n = a( [(n+1)/3] ).


PROG

(PARI) a(n) = valuation((6*n)!, 3)  valuation((3*n)!, 3); \\ Michel Marcus, Jul 29 2017


CROSSREFS

Cf. A007949, A054861, A004128.
Sequence in context: A100614 A274231 A173999 * A286994 A047205 A283765
Adjacent sequences: A127424 A127425 A127426 * A127428 A127429 A127430


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Apr 02 2007


STATUS

approved



