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A174785 Expansion of (1+2x-x^2+x^3-x^4-x^5)/(1+x^3)^2. 1
1, 2, -1, -1, -5, 1, 1, 8, -1, -1, -11, 1, 1, 14, -1, -1, -17, 1, 1, 20, -1, -1, -23, 1, 1, 26, -1, -1, -29, 1, 1, 32, -1, -1, -35, 1, 1, 38, -1, -1, -41, 1, 1, 44, -1, -1, -47, 1, 1, 50, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Hankel transform of A174783(n+1).
LINKS
FORMULA
a(n)=(n+4)*cos(pi*n/3)/3+n*sin(pi*n/3)/sqrt(3)-(n+1)*(-1)^n/3.
MATHEMATICA
CoefficientList[Series[(1+2x-x^2+x^3-x^4-x^5)/(1+x^3)^2, {x, 0, 50}], x] (* or *) LinearRecurrence[{0, 0, -2, 0, 0, -1}, {1, 2, -1, -1, -5, 1}, 60] (* Harvey P. Dale, May 11 2019 *)
CROSSREFS
Sequence in context: A210545 A141323 A210876 * A356399 A136789 A342916
KEYWORD
easy,sign
AUTHOR
Paul Barry, Mar 29 2010
STATUS
approved

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Last modified March 28 11:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)