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A087440
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Expansion of (1-2x-3x^2)/((1-2x)(1-4x)).
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2
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1, 4, 13, 46, 172, 664, 2608, 10336, 41152, 164224, 656128, 2622976, 10488832, 41949184, 167784448, 671113216, 2684403712, 10737516544, 42949869568, 171799085056, 687195553792, 2748780642304, 10995119423488, 43980471402496
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OFFSET
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0,2
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COMMENTS
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Binomial transform is A087439. Second binomial transform of A084221 (with extra leading 1).
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LINKS
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FORMULA
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a(n) = 5*4^n/8 + 3*2^n/4 - 3*0^n/8.
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MATHEMATICA
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CoefficientList[Series[(1-2x-3x^2)/((1-2x)(1-4x)), {x, 0, 30}], x] (* or *) Join[{1}, LinearRecurrence[{6, -8}, {4, 13}, 30]] (* Harvey P. Dale, Jan 18 2012 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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