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例子
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a(6)=8,因为我们有[5,1],[3,2,1],[3],1,2],[2,3,1],[2,1,3],[1,5],[1,3,2]和[1,2,3]。
a(1)=1到a(8)=16组分(空列用点表示):
(1) . (1,2) (1,3) (1,4) (1,5) (1,6) (1,7)
(2,1)(3,1)(2,3)(5,1)(2,5)(3,5)
(3,2) (1,2,3) (3,4) (5,3)
(4,1) (1,3,2) (4,3) (7,1)
(2,1,3) (5,2) (1,2,5)
(2,3,1) (6,1) (1,3,4)
(3,1,2)(1,2,4)(1,4,3)
(3,2,1) (1,4,2) (1,5,2)
(2,1,4) (2,1,5)
(2,4,1) (2,5,1)
(4,1,2) (3,1,4)
(4,2,1) (3,4,1)
(4,1,3)
(4,3,1)
(5,1,2)
(5,2,1)
(结束)
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