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A188479
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Binomial variation of the Catalan Numbers
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2
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1, 1, 2, 4, 12, 40, 156, 700, 3520, 19592, 119992, 801272, 5792464, 45071600, 375615696, 3338063600, 31511918816, 314913425280, 3321357021600, 36868596345056, 429672869359360, 5245439731918784, 66941714022827072, 891387254398818752, 12363478873222765568, 178331546692362644992, 2671094825005048612224
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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( binomial(n-i, i)*a(i)*a(n-1-i), i=0..(n-1) ) with a(0)=1
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MATHEMATICA
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a[0]=1; a[n_]:=a[n]=Sum[ Binomial[n-i, i] a[i]*a[n-1-i], {i, 0, n-1}]; Table[ a[n], {n, 0, 30}]
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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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