A057005 -id:A057005 - cp's OEIS frontend

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A069738 Number of isomorphism classes of minimal n-extensions of a kind of homeomorphism of the circle.

Original entry on oeis.org

1, 3, 7, 26, 97, 624, 4162, 34469

Offset: 1

Valery A. Liskovets, Apr 15 2002

There is a formula in terms of conjugacy classes of transitive pairs and triples of permutations of degree n (A057005 and A057006).

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.

Cf. A057005, A057006.

A214822 Number of genus 1 unsensed hypermaps with n darts.

Original entry on oeis.org

0, 0, 1, 6, 30, 211, 1350, 9636, 69169, 513012, 3843024, 29107494

Offset: 1

N. J. A. Sloane, Aug 01 2012

Timothy R. Walsh, Space-efficient generation of nonisomorphic maps and hypermaps
T. R. Walsh, Space-Efficient Generation of Nonisomorphic Maps and Hypermaps, J. Int. Seq. 18 (2015) # 15.4.3

Cf. A090371, A118094, A214819, A214820, A057005; A214821-A214823, A215017, A215018.

A289678 Number of hypermaps which are self-equivalent with respect to reversing the colors of the nodes and which have n edges.

Original entry on oeis.org

1, 1, 3, 6, 15, 42, 131, 442, 1551, 5723, 22171, 89156, 370199, 1589240, 7020127, 31906974

Offset: 1

N. J. A. Sloane, Aug 03 2017

M. Deryagina, On the enumeration of hypermaps which are self-equivalent with respect to reversing the colors of vertices, Preprint 2016.

Cf. A057005, A234278.

a(n) = 2*A234278(n) - 2*A057005(n).

Previous Showing 11-13 of 13 results.