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评论
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反链是有限集合的有限集合,其中没有一个是其他集合的子集。如果它的并集是{1..n},则它是覆盖的。边和是每条边中顶点的和,因此例如,{{1,3}、{2,5}、}3,4,5}}的边和是{4,7,12}。
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例子
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a(0)=2到a(3)=8反链:
{} {{1}} {{1,2}} {{1,2,3}}
{{}} {{1},{2}} {{1},{2,3}}
{{2},{1,3}}
{{1,2},{1,3}}
{{1,2},{2,3}}
{{1},{2},{3}}
{{1,3},{2,3}}
{{1,2}、{1,3}、{2,3}
a(4)=80反链:
{1234} {1}{234} {1}{2}{34} {1}{2}{3}{4} {12}{13}{14}{24}{34}
{12} {34}{1}{3}{24}{1}{23}{24}{34}{12}{13}{23}{24}{34}
{13}{24} {1}{4}{23} {2}{13}{14}{34}
{2}{134} {2}{3}{14} {12}{13}{14}{24}
{3}{124} {1}{23}{24} {12}{13}{14}{34}
{4} {123}{1}{23}{34}{12}{13}{23}{24}
{12}{134} {1}{24}{34} {12}{13}{23}{34}
{12}{234} {2}{13}{14} {12}{13}{24}{34}
{13}{124} {2}{13}{34} {12}{14}{24}{34}
{13}{234} {2}{14}{34} {12}{23}{24}{34}
{14}{123} {3}{14}{24} {13}{14}{24}{34}
{14}{234} {4}{12}{23} {13}{23}{24}{34}
{23}{124} {12}{13}{14} {12}{13}{14}{234}
{23}{134} {12}{13}{24} {12}{23}{24}{134}
{24}{134} {12}{13}{34} {123}{124}{134}{234}
{34}{123} {12}{14}{34}
{123}{124} {12}{23}{24}
{123}{134} {12}{23}{34}
{123}{234} {12}{24}{34}
{124}{134} {13}{14}{24}
{124}{234} {13}{23}{24}
{134}{234} {13}{23}{34}
{13} {24}{34}
{14}{24}{34}
{12}{13}{234}
{12}{14}{234}
{12}{23}{134}
{12}{24}{134}
{13}{14}{234}
{13}{23}{124}
{14}{34}{123}
{23}{24}{134}
{12}{134}{234}
{13}{124}{234}
{14}{123}{234}
{23}{124}{134}
{123}{124}{134}
{123}{124}{234}
{123}{134}{234}
{124}{134}{234}
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