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A186186
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Expansion of 1/(1-x/(1-x)*A(x/(1-x))) where A(x) is the g.f. of A002293.
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1
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1, 1, 3, 12, 63, 403, 2919, 22833, 187799, 1599718, 13984383, 124717327, 1130144932, 10375309228, 96290993853, 901915801437, 8514822062757, 80939662475426, 774025387921462, 7441380898249458, 71879194326339456, 697253570563306939, 6789448668631285664, 66340474776507262638
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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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a(n) = Sum_{m=1..n} Sum_{k=m..n} binomial(n-1,k-1)*m/(3*k-2*m)*binomial(4*k-3*m-1,k-m), n>0, a(0)=1.
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PROG
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(PARI) a(n)={if(n<1, n==0, sum(m=1, n, sum(k=m, n, binomial(n-1, k-1)*m/(3*k-2*m)*binomial(4*k-3*m-1, k-m))))} \\ Andrew Howroyd, Apr 17 2021
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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