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A278023
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G.f.: 2*x*(1-x*sqrt(1-4*x))/((1+2*x^2+sqrt(1-4*x))*sqrt(1-4*x)).
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1
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0, 1, 2, 8, 30, 109, 401, 1495, 5623, 21289, 81034, 309817, 1188932, 4576980, 17667647, 68359881, 265045494, 1029512644, 4005417845, 15606129991, 60885118375, 237816401610, 929909358659, 3639712494186, 14258889345834, 55906875628333, 219370377887309, 861389105627213, 3384600499000626
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OFFSET
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0,3
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LINKS
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FORMULA
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Conjecture: +n*(3*n^2-12*n+11) *a(n) -(3*n-5) *(3*n^2-9*n+4) *a(n-1) -2*(2*n-5) *(3*n^2-6*n+2) *a(n-2) +n *(3*n^2-12*n+11) *a(n-3) -2 *(2*n-5) *(3*n^2-6*n+2) *a(n-4)=0. - R. J. Mathar, Jun 24 2018
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MATHEMATICA
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CoefficientList[Series[2*x*(1-x*Sqrt[1-4*x])/(Sqrt[1-4*x]*(1+2*x^2+Sqrt[1-4*x])), {x, 0, 20}], x] (* Vaclav Kotesovec, Nov 10 2016 *)
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PROG
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(PARI) x='x+O('x^50); concat([0], Vec(2*x*(1-x*sqrt(1-4*x) )/( (1+ 2*x^2 +sqrt(1-4*x))*sqrt(1-4*x)))) \\ G. C. Greubel, Jun 05 2017
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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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