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A174191
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Expansion of (1+x)*(2*x-1)/((1-x)*(x^2+2*x-1)).
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1
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1, 2, 3, 6, 13, 30, 71, 170, 409, 986, 2379, 5742, 13861, 33462, 80783, 195026, 470833, 1136690, 2744211, 6625110, 15994429, 38613966, 93222359, 225058682, 543339721, 1311738122, 3166815963, 7645370046, 18457556053, 44560482150, 107578520351
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OFFSET
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0,2
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COMMENTS
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Pisano period lengths: 1, 2, 8, 4, 12, 8, 6, 8, 24, 12, 24, 8, 28, 6, 24, 16, 16, 24, 40, 12,.. (is this A175181?) - R. J. Mathar, Aug 10 2012
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LINKS
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FORMULA
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a(n) = 2*a(n-1) + a(n-2) - 2, with a(0)=1, a(1)=2.
a(n) = 3*a(n-1) - a(n-2) - a(n-3). (End)
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EXAMPLE
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a(2) = 2*a(1) + a(0) - 2 = 2*2 + 1 - 2 = 3
a(3) = 2*a(2) + a(1) - 2 = 2*3 + 2 - 2 = 6.
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MATHEMATICA
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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