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A123889
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Expansion of g.f.: x/((1-x^2)^4 -1+x).
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1
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1, 4, 16, 58, 208, 740, 2628, 9327, 33096, 117432, 416668, 1478400, 5245576, 18612052, 66038209, 234312956, 831375680, 2949839102, 10466448480, 37136447100, 131765393560, 467522347871, 1658835752336, 5885785066224, 20883602126968, 74097989119616
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OFFSET
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0,2
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LINKS
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MAPLE
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seq(coeff(series(1/(1-4*x+6*x^3-4*x^5+x^7), x, n+1), x, n), n = 0 .. 30); # G. C. Greubel, Aug 07 2019
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MATHEMATICA
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CoefficientList[Series[x/((1-x^2)^4 -1+x), {x, 0, 30}], x] (* G. C. Greubel, Aug 07 2019 *)
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PROG
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(PARI) my(x='x+O('x^30)); Vec(x/((1-x^2)^4 -1+x)) \\ G. C. Greubel, Aug 07 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 30); Coefficients(R!( x/((1-x^2)^4 -1+x) )); // G. C. Greubel, Aug 07 2019
(Sage)
P.<x> = PowerSeriesRing(ZZ, prec)
return P( x/((1-x^2)^4 -1+x) ).list()
(GAP) a:=[1, 4, 16, 58, 208, 740, 2628];; for n in [8..30] do a[n]:=4*a[n-1] -6*a[n-3] +4*a[n-5]-a[n-7]; od; a; # G. C. Greubel, Aug 07 2019
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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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