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

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

Offset

1,3

Links

Table of n, a(n) for n=1..16.

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

Formula

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

Crossrefs

Cf. A057005, A234278.

Sequence in context: A001433 A005368 A067771 * A337326 A056382 A028401

Adjacent sequences: A289675 A289676 A289677 * A289679 A289680 A289681

Keyword

nonn,more

Author

N. J. A. Sloane, Aug 03 2017

Status

approved