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A134430
Period 4: repeat [1, -2, -2, 1].
1
1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2, -2, 1, 1, -2
OFFSET
0,2
FORMULA
Binomial transform of A134813.
|a(n)| = A014695(n).
G.f.: (1-3*x+x^2) / ((1-x)*(1+x^2)). - R. J. Mathar, Jan 18 2011
From Wesley Ivan Hurt, Jul 09 2016: (Start)
a(n) = a(n-1) - a(n-2) + a(n-3) for n>2, a(n) = a(n-4) for n>3.
a(n) = (3*cos(n*Pi/2) - 3*sin(n*Pi/2) - 1)/2. (End)
MAPLE
seq(op([1, -2, -2, 1]), n=0..40); # Wesley Ivan Hurt, Jul 09 2016
MATHEMATICA
PadRight[{}, 100, {1, -2, -2, 1}] (* Wesley Ivan Hurt, Jul 09 2016 *)
PROG
(Magma) &cat [[1, -2, -2, 1]^^30]; // Wesley Ivan Hurt, Jul 09 2016
CROSSREFS
Sequence in context: A270646 A293540 A073783 * A130658 A014695 A211263
KEYWORD
sign,easy
AUTHOR
Paul Curtz, Jan 31 2008
STATUS
approved