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A257596
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G.f.: (1-x)*(1-2*x-x^2-(1-x)*sqrt(1-2*x-3*x^2))/(2*x*(1-2*x-x^2)).
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0
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0, 0, 1, 3, 10, 30, 88, 252, 712, 1992, 5537, 15323, 42286, 116506, 320773, 883191, 2433112, 6709832, 18529067, 51251265, 142021430, 394336930, 1097215414, 3059549286, 8550284176, 23947824960, 67221675367, 189102714045, 533104654538
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OFFSET
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1,4
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LINKS
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FORMULA
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D-finite with recurrence: +(n+1)*a(n) +(-5*n+1)*a(n-1) +4*(n-2)*a(n-2) +8*(n-2)*a(n-3) +(-5*n+31)*a(n-4) +3*(-n+5)*a(n-5)=0. - R. J. Mathar, Jun 12 2015
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MAPLE
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(1-x)*(1-2*x-x^2-(1-x)*sqrt(1-2*x-3*x^2))/(2*x*(1-2*x-x^2)) ;
taylor(%, x=0, 40) ;
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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