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A026739
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Number of subgroups L of Z^n with the property that for every a in Z^n there exists precisely one b in L with d(a,b) <= 1. Here d denotes Euclidean distance.
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0
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1, 1, 2, 8, 72, 384, 3840, 80640, 645120, 10321920, 309657600, 3715891200, 102187008000, 3310859059200, 51011754393600, 1428329123020800, 68559797904998400, 1942527607308288000
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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) = 2^n*n!*sum(1/|Aut(G)|), where the sum is over all isomorphism classes of Abelian groups of order 2*n+1.
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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