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A171557 a(n) = 3^n*A168053(n). 1
1, 3, -9, -81, -243, -1215, -5103, -15309, -59049, -216513, -649539, -2302911, -7971615, -23914845, -81310473, -272629233, -817887699, -2711943423, -8910671247, -26732013741, -87169610025, -282429536481, -847288609443 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Hankel transform of A171556.
LINKS
FORMULA
G.f.: (1-18*x^2-81*x^3)/((1-3*x)^2*(1+3*x+9*x^2)).
MATHEMATICA
CoefficientList[Series[(1 - 18 x^2 - 81 x^3)/((1 - 3 x)^2*(1 + 3 x + 9 x^2)), {x, 0, 30}], x] (* Wesley Ivan Hurt, Jan 21 2017 *)
PROG
(PARI) Vec((1-18*x^2-81*x^3)/((1-3*x)^2*(1+3*x+9*x^2)) + O(x^30)) \\ Michel Marcus, Feb 10 2015
CROSSREFS
Sequence in context: A259986 A124049 A067623 * A055156 A047912 A078684
KEYWORD
easy,sign
AUTHOR
Paul Barry, Dec 11 2009
STATUS
approved

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Last modified June 14 14:51 EDT 2024. Contains 373400 sequences. (Running on oeis4.)