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A279136
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a(n) = n*Sum_{i=0..n-1} binomial(n,i)*binomial(i-1,n-i-1)/(n-i).
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0
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0, 1, 3, 10, 27, 76, 210, 589, 1659, 4708, 13428, 38479, 110682, 319411, 924339, 2681410, 7794939, 22702396, 66229212, 193495279, 566069052, 1658026093, 4861703289, 14269842184, 41922504570, 123265254451, 362719839225, 1068105234304
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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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G.f.: (3*x^3+sqrt(-3*x^2-2*x+1)*(x^2+4*x-3)-3*x^2-7*x+3)/(sqrt(-3*x^2-2*x+1)*(2*x^3-x^2-2*x+1)-3*x^3+x^2+3*x-1).
D-finite with recurrence: +n*a(n) +(-3*n+2)*a(n-1) +2*(-n+1)*a(n-2) +2*(3*n-7)*a(n-3) +(n-2)*a(n-4) +3*(-n+4)*a(n-5)=0. - R. J. Mathar, Mar 12 2017
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PROG
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(Maxima)
(3*x^3+sqrt(-3*x^2-2*x+1)*(x^2+4*x-3)-3*x^2-7*x+3)/(sqrt(-3*x^2-2*x+1)*(2*x^3-x^2-2*x+1)-3*x^3+x^2+3*x-1);
taylor(%, x, 0, 27);
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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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