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A144901
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Expansion of x/((1-x-x^3)*(1-x)^7).
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8
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0, 1, 8, 36, 121, 339, 837, 1882, 3937, 7777, 14664, 26609, 46762, 79990, 133731, 219253, 353507, 561851, 882051, 1370154, 2109105, 3221386, 4887550, 7373395, 11069801, 16551126, 24660802, 36636795, 54295489, 80301195, 118561150, 174804431, 257430410
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OFFSET
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0,3
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LINKS
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Index entries for linear recurrences with constant coefficients, signature (8,-28,57,-77,77,-63,43,-22,7,-1).
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FORMULA
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G.f.: x/((1-x-x^3)*(1-x)^7).
a(n) = Sum_{j=0..floor((n+6)/3)} binomial(n-2*j+6, j+7).
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MAPLE
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a:= n-> (Matrix(10, (i, j)-> if i=j-1 then 1 elif j=1 then [8, -28, 57, -77, 77, -63, 43, -22, 7, -1][i] else 0 fi)^n)[1, 2]: seq(a(n), n=0..40);
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MATHEMATICA
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CoefficientList[Series[x/((1-x-x^3)(1-x)^7), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 06 2013 *)
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PROG
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(Magma)
A144901:= func< n | n eq 0 select 0 else (&+[Binomial(n-2*j+6, j+7): j in [0..Floor((n+6)/3)]]) >;
(SageMath)
def A144901(n): return sum(binomial(n-2*j+6, j+7) for j in (0..((n+6)//3)))
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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