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A069738
Number of isomorphism classes of minimal n-extensions of a kind of homeomorphism of the circle.
0
1, 3, 7, 26, 97, 624, 4162, 34469
OFFSET
1,2
COMMENTS
There is a formula in terms of conjugacy classes of transitive pairs and triples of permutations of degree n (A057005 and A057006).
REFERENCES
N. G. Markley and W. N. Anderson,jun, An application of Moebius inversion to a problem in topological dynamics. Bull. Amer. Math. Soc. 79 (1973), 1027-1029.
V. A. Liskovets, On a combinatorial problem of the theory of topological transformations of the circle. Vesci AN BSSR (ser. fiz.-mat.), No 4 (1976), 29-34 (in Russian), Math. Rev. 58 #7575.
CROSSREFS
Sequence in context: A258311 A184459 A215018 * A057005 A158561 A252786
KEYWORD
more,nonn
AUTHOR
Valery A. Liskovets, Apr 15 2002
STATUS
approved