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A117575 Expansion of (1-x^3)/((1-x)(1+2x^2)). +0
2
1, 1, -1, -2, 2, 4, -4, -8, 8, 16, -16, -32, 32, 64, -64, -128, 128, 256, -256, -512, 512, 1024, -1024, -2048, 2048, 4096, -4096, -8192, 8192, 16384, -16384, -32768, 32768, 65536, -65536, -131072, 131072, 262144, -262144, -524288, 524288 (list; graph; listen)
OFFSET

0,4

COMMENT

Row sums of A116949.

FORMULA

a(n)=a(n-1)-2a(n-2)+2a(n-3), n>3; a(n)=(cos(pi*/2)+sin(pi*n/2))*(2^((n-1)/2)(1-(-1)^n)/2+2^((n-2)/2)(1+(-1)^n)/2+0^n/2).

CROSSREFS

Sequence in context: A076939 A131572 A158780 this_sequence A152166 A016116 A060546

Adjacent sequences: A117572 A117573 A117574 this_sequence A117576 A117577 A117578

KEYWORD

easy,sign

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Mar 29 2006

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.


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