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A177002
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Period 4: repeat [1, 2, 4, 2].
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2
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1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2, 4, 2, 1, 2
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OFFSET
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0,2
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COMMENTS
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Also the decimal expansion of 138/1111 and the continued fractions of (5+3*sqrt(10))/10 or (6*sqrt(10)-10)/13. - R. J. Mathar, Dec 13 2010
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LINKS
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FORMULA
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G.f.: (1+2*x+4*x^2+2*x^3)/((1-x)*(1+x)*(x^2+1)). - R. J. Mathar, Dec 13 2010
a(n) = a(n-1) * a(n-3) / a(n-2) for n>2. - Bruno Berselli, Feb 04 2013
a(n) = a(n-4) for n>3.
a(n) = (9 + cos(n*Pi) - 6*cos(n*Pi/2))/4. (End)
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MAPLE
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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