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A067623 Consider the power series (x+1)^(1/3)=1+x/3-x^2/9+5x^3/81+...; sequence gives denominators of coefficients. 2
1, 3, 9, 81, 243, 729, 6561, 19683, 59049, 1594323, 4782969, 14348907, 129140163, 387420489, 1162261467, 10460353203, 31381059609, 94143178827, 2541865828329, 7625597484987, 22876792454961, 205891132094649, 617673396283947 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

All terms are powers of 3.

LINKS

Table of n, a(n) for n=0..22.

FORMULA

a(n) = 3^A004128(n).

a(n) = 3^n*a(floor(n/3)). - Vladeta Jovovic, Mar 01 2004

a(n) = denominator(binomial(1/3, n)). - Peter Luschny, Apr 07 2016

MAPLE

A067623 := n -> denom(binomial(1/3, n)):

seq(A067623(n), n=0..21); # Peter Luschny, Apr 07 2016

MATHEMATICA

Table[Denominator@ Binomial[1/3, n], {n, 0, 22}] (* Michael De Vlieger, Apr 07 2016 *)

CROSSREFS

Cf. A004128, A046161, A067622 (numerators), A123854.

Sequence in context: A139731 A259986 A124049 * A171557 A055156 A047912

Adjacent sequences:  A067620 A067621 A067622 * A067624 A067625 A067626

KEYWORD

nonn,frac

AUTHOR

Benoit Cloitre, Feb 02 2002

STATUS

approved

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Last modified September 25 06:44 EDT 2016. Contains 276528 sequences.