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A339644飞机 |
| n个节点上标签覆盖正整数初始区间的根树数。 |
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2
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1, 3, 21, 214, 3004, 53696, 1169220, 30017582, 887835091, 29728120594, 1111619802614, 45914106227815, 2076062017348677, 101996651482313080, 5410363994433018486, 308174409706787225523, 18760485689929220881741, 1215547422537201878074293, 83520534389622385511232635
(列表;图表;参考;听;历史;文本;内部格式)
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抵消
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1,2
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链接
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例子
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a(3)=21根树为:
(1(11)), (1(1(1))), (1(12)), (1(22)), (1(1(2))), (1(2(1))), (1(2(2))), (2(12)), (2(11)), (2(2(1))), (2(1(2))), (2(1(1))), (1(23)), (1(2(3))), (1(3(2))), (2(13)), (2(1(3))), (2(3(1))), (3(12)), (3(1(2))), (3(2(1))).
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MAPLE公司
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b: =proc(n,k)选项记忆`如果`(n<2,k*n,(加上(b(d,k)*
d、 d=数值[除数](j))*b(n-j,k),j=1..n-1))/(n-1)
结束时间:
a: =n->加(加(b(n,k-j)*二项式(k,j)*(-1)^j,j=0..k),k=0..n):
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数学
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b[n_,k_]:=b[n,k]=如果[n<2,k*n,(总和[b[d,k]*d,{d,除数[j]}]*b[n-j,k],{j,1,n-1}])/(n-1)];
a[n]:=和[Sum[b[n,k-j]*二项式[k,j]*(-1)^j,{j,0,k}],{k,0,n}];
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黄体脂酮素
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seq(n)={sum(k=1,n,U(n,k)*sum(r=k,n,二项式(r,k)*(-1)^(r-k))}
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交叉参考
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关键词
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非n
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作者
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状态
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经核准的
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