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0, 0, 2, 1, 6, 3, 12, 6, 20, 10, 30, 15, 42, 21, 56, 28, 72, 36, 90, 45, 110, 55, 132, 66, 156, 78, 182, 91, 210, 105, 240, 120, 272, 136, 306, 153, 342, 171, 380, 190, 420, 210, 462, 231, 506, 253, 552, 276, 600, 300, 650, 325, 702, 351, 756, 378, 812, 406, 870, 435
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = 3*a(n-2)-3*a(n-4)+a(n-6).
G.f.: x^2*(2+x)/((1-x)^3*(1+x)^3). [R. J. Mathar, Jul 17 2009]
a(n) = (3*n^2+4*n-1+(n^2+4*n+1)*(-1)^n)/16. - Luce ETIENNE, Aug 19 2014
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MAPLE
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MATHEMATICA
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LinearRecurrence[{0, 3, 0, -3, 0, 1}, {0, 0, 2, 1, 6, 3}, 60] (* Harvey P. Dale, Jun 01 2012 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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