A379438 Triangle read by rows: T(n,k) is the number of sensed combinatorial maps with n edges and genus k, 0 <= k <= floor(n/2).
1, 2, 4, 1, 14, 6, 57, 46, 4, 312, 452, 106, 2071, 4852, 2382, 131, 15030, 52972, 46680, 8158, 117735, 587047, 830848, 313611, 14118, 967850, 6550808, 13804864, 9326858, 1369446, 8268816, 73483256, 218353000, 236095958, 74803564, 2976853, 72833730, 827801468, 3328822880, 5345316004, 3023693380, 391288854
Offset: 0
Examples
Triangle begins: n\k [0] [1] [2] [3] [4] [0] 1; [1] 2; [2] 4, 1; [3] 14, 6; [4] 57, 46, 4; [5] 312, 452, 106; [6] 2071, 4852, 2382, 131; [7] 15030, 52972, 46680, 8158; [8] 117735, 587047, 830848, 313611, 14118; [9] 967850, 6550808, 13804864, 9326858, 1369446; ...
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..120 (rows 0..20)
- 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, Alain Giorgetti, and Alexander Mednykh, Enumeration of unrooted orientable maps of arbitrary genus by number of edges and vertices, Discrete Math. 312 (2012), no. 17, 2660--2671. MR2935417.