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A145135
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Expansion of x/((1 - x - x^4)*(1 - x)^6).
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5
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0, 1, 7, 28, 84, 211, 470, 960, 1836, 3334, 5806, 9769, 15973, 25495, 39869, 61266, 92743, 138587, 204790, 299705, 434952, 626669, 897239, 1277674, 1810906, 2556330, 3596075, 5043660, 7055942, 9849608, 13723939, 19092231, 26525165
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OFFSET
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0,3
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COMMENTS
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The coefficients of the recursion for a(n) are given by the 7th row of A145152.
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LINKS
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FORMULA
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a(n) = 7a(n-1) -21a(n-2) +35a(n-3) -34a(n-4) +15a(n-5) +8a(n-6) -19a(n-7) +15a(n-8) -6a(n-9) +a(n-10).
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MAPLE
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col:= proc(k) local l, j, M, n; l:= `if`(k=0, [1, 0, 0, 1], [seq(coeff ( -(1-x-x^4) *(1-x)^(k-1), x, j), j=1..k+3)]); M:= Matrix(nops(l), (i, j)-> if i=j-1 then 1 elif j=1 then l[i] else 0 fi); `if`(k=0, n->(M^n)[2, 3], n->(M^n)[1, 2]) end: a:= col(7): seq(a(n), n=0..40);
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MATHEMATICA
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CoefficientList[Series[x / ((1 - x - x^4) (1 - x)^6), {x, 0, 50}], x] (* Vincenzo Librandi, Jun 06 2013 *)
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PROG
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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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