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A190967
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a(n) = 4*a(n-1) - 9*a(n-2), with a(0)=0, a(1)=1.
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2
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0, 1, 4, 7, -8, -95, -308, -377, 1264, 8449, 22420, 13639, -147224, -711647, -1521572, 318535, 14968288, 57006337, 93310756, -139814009, -1399052840, -4337885279, -4760065556, 20000705287, 122843411152, 311367297025, 139878487732, -2242791722297
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OFFSET
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0,3
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LINKS
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Table of n, a(n) for n=0..27.
Index to sequences with linear recurrences with constant coefficients, signature (4,-9)
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FORMULA
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a(n)=(1/10*I)*sqrt(5)*((2-I*sqrt(5))^n -(2+I*sqrt(5))^n), Paolo P. Lava, May 31 2011
G.f.: x/(1-4x+9*x^2). - From Philippe Deléham, Oct 12 2011.
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MATHEMATICA
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LinearRecurrence[{4, -9}, {0, 1}, 50]
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CROSSREFS
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Cf. A190958 (index to generalized Fibonacci sequences)
Sequence in context: A160629 A093105 A141669 * A004787 A210617 A191762
Adjacent sequences: A190964 A190965 A190966 * A190968 A190969 A190970
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KEYWORD
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sign,easy
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AUTHOR
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Vladimir Joseph Stephan Orlovsky, May 24 2011
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STATUS
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approved
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