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A131608 Period 24: repeat 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, -1, -1, -3, -7, -7, -1, -9, -9, -7, -3, -3, -9. 0
1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, -1, -1, -3, -7, -7, -1, -9, -9, -7, -3, -3, -9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, -1, -1, -3, -7, -7, -1, -9, -9, -7, -3, -3, -9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, -1, -1, -3, -7, -7, -1, -9, -9, -7, -3, -3, -9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, -1, -1, -3, -7, -7, -1, -9, -9, -7, -3, -3, -9 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

FORMULA

a(n)= -a(n-12).

G.f. (1+x)*(1+x+x^2)*(x^2-x+1)*(9*x^6-6*x^5+4*x^3+2*x^2+1) / ( (1+x^4)*(x^8-x^4+1) ). - R. J. Mathar, Oct 08 2011

CROSSREFS

Sequence in context: A060924 A013564 A009467 * A131707 A016620 A200691

Adjacent sequences:  A131605 A131606 A131607 * A131609 A131610 A131611

KEYWORD

sign,easy

AUTHOR

Paul Curtz (bpcrtz(AT)free.fr), Oct 02 2007

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Last modified February 17 07:41 EST 2012. Contains 205998 sequences.