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A117902 Expansion of (1-x^2-2x^3)/(1-4x^3). 2
1, 0, -1, 2, 0, -4, 8, 0, -16, 32, 0, -64, 128, 0, -256, 512, 0, -1024, 2048, 0, -4096, 8192, 0, -16384, 32768, 0, -65536, 131072, 0, -262144, 524288, 0, -1048576, 2097152, 0, -4194304, 8388608, 0, -16777216, 33554432, 0, -67108864, 134217728, 0, -268435456, 536870912, 0, -1073741824 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Row sums of number triangle A117901.

LINKS

Table of n, a(n) for n=0..47.

FORMULA

a(n)=0^n/2-2^(2n/3)(cos(2*pi*n/3+pi/3)/6+sqrt(3)*sin(2*pi*n/3+pi/3)/6 -(2^(2/3)/12+2/3)cos(2*pi*n/3)-432^(1/6)*sin(2*pi*n/3)/12+2^(2/3)/12-1/6)

CROSSREFS

Sequence in context: A011121 A255643 A230277 * A021087 A120558 A325416

Adjacent sequences:  A117899 A117900 A117901 * A117903 A117904 A117905

KEYWORD

easy,sign

AUTHOR

Paul Barry, Apr 01 2006

STATUS

approved

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Last modified October 18 05:31 EDT 2019. Contains 328146 sequences. (Running on oeis4.)