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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
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
MATHEMATICA
PadRight[{}, 100, {1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, -1, -1, -3, -7, -7, -1, -9, -9, -7, -3, -3, -9}] (* Harvey P. Dale, Jun 09 2015 *)
CROSSREFS
Sequence in context: A373862 A353049 A288093 * A131707 A348722 A349614
KEYWORD
sign,easy
AUTHOR
Paul Curtz, Oct 02 2007
STATUS
approved