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A051111
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Expansion of x/(x^4-3*x^3+4*x^2-2*x+1).
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0
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0, 1, 2, 0, -5, -5, 8, 21, 0, -55, -55, 89, 233, 0, -610, -610, 987, 2584, 0, -6765, -6765, 10946, 28657, 0, -75025, -75025, 121393, 317811, 0, -832040, -832040, 1346269, 3524578, 0, -9227465, -9227465, 14930352, 39088169, 0, -102334155, -102334155
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OFFSET
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1,3
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LINKS
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FORMULA
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a(5*n + 1) = F(5*n + 1), a(5*n + 2) = F(5*n + 3), a(5*n + 3) = 0, a(5*n - 1) = a(5*n) = -F(5*n), where F = A000045 the Fibonacci sequence.
G.f.: x / (x^4 - 3*x^3 + 4*x^2 - 2*x + 1). - Michael Somos, Apr 25 2003
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EXAMPLE
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x + 2*x^2 - 5*x^4 - 5*x^5 + 8*x^6 + 21*x^7 - 55*x^9 - 55*x^10 + 89*x^11 + ...
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MATHEMATICA
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CoefficientList[Series[x/(x^4-3x^3+4x^2-2x+1), {x, 0, 40}], x] (* or *) LinearRecurrence[{2, -4, 3, -1}, {0, 1, 2, 0}, 50] (* Harvey P. Dale, Aug 09 2020 *)
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PROG
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(PARI) {a(n) = local(x, y); x = fibonacci(n); y = fibonacci(n+1); [ -x, x, y, 0, -y][n%5 + 1]}
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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