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A026739 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. 0
1, 1, 2, 8, 72, 384, 3840, 80640, 645120, 10321920, 309657600, 3715891200, 102187008000, 3310859059200, 51011754393600, 1428329123020800, 68559797904998400, 1942527607308288000 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
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.
CROSSREFS
Sequence in context: A180687 A356811 A296629 * A060635 A364408 A194499
KEYWORD
easy,nonn
AUTHOR
Paul Boddington, Jan 26 2004
STATUS
approved

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Last modified March 19 01:34 EDT 2024. Contains 370952 sequences. (Running on oeis4.)