A214816 Number of unsensed combinatorial maps with n edges on an orientable surface of any genus.

1, 2, 5, 20, 96, 644, 5839, 67834, 970568, 16256556, 308620966, 6506035400, 150358570914, 3775903806928, 102348067516576, 2977979542305736, 92579723269733557, 3062602106878957610, 107418879166917701583, 3981908920500346885116, 155550644128029095714786

Offset

0,2

Links

Andrew Howroyd, Table of n, a(n) for n = 0..30

Antonio Breda d'Azevedo, Alexander Mednykh, and Roman Nedela, Enumeration of maps regardless of genus: Geometric approach, Discrete Mathematics, Volume 310, 2010, Pages 1184-1203.

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.

Formula

a(n) = (A170946(n) + A170947(n)) / 2. [Breda d'Azevedo, Mednykh & Nedela, Corollary 4.7] - Andrey Zabolotskiy, Jun 06 2024

Crossrefs

Row sums of A379439.

Cf. A006385, A006387, A170946 (sensed), A170947 (achiral), A170948 (chiral pairs), A214814, A214815, A297880, A297881, A348798, A348800, A348801.

Sequence in context: A115082 A020105 A347071 * A020005 A259834 A074415

Adjacent sequences: A214813 A214814 A214815 * A214817 A214818 A214819

Keyword

nonn

Author

N. J. A. Sloane, Jul 31 2012

Extensions

a(12)-a(18) from Andrey Zabolotskiy, Jun 06 2024

a(19) onwards from Andrew Howroyd, Jan 27 2025

Status

approved