A380235 Triangle read by rows: T(n,k) is the number of n edge non-orientable genus k maps.

1, 4, 2, 19, 16, 8, 106, 137, 128, 47, 709, 1254, 1890, 1372, 473, 5356, 12597, 27036, 31007, 22556, 7190, 44558, 133518, 379491, 611322, 704066, 469632, 144904, 397146, 1464725, 5229092, 11017122, 17691240, 18521632, 11990766, 3534490, 3716039, 16373700, 70805740, 186044902, 387965547, 563764626, 571333104, 352456980, 100895667

Offset: 1

Author

Andrew Howroyd, Jan 17 2025

Keywords

• nonn
• tabl

Examples

			Triangle begins:
      1;
      4,      2;
     19,     16,      8;
    106,    137,    128,     47;
    709,   1254,   1890,   1372,    473;
   5356,  12597,  27036,  31007,  22556,   7190;
  44558, 133518, 379491, 611322, 704066, 469632, 144904;
  ...
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..105 (rows 1..14)
• Evgeniy Krasko and Alexander Omelchenko, Enumeration of Unsensed Orientable Maps on Surfaces of a Given Genus, arXiv:1712.10139 [math.CO], 2017, see Appendix Tables 5-7.
• Evgeniy Krasko, Maps on non-orientable surfaces, 2017 (data file).

Crossrefs

Main diagonal is A380236.

Columns k=1..10 are A348802, A348803, A348804, A348805, A348806, A348807, A348808, A348809, A348810, A348811.

Cf. A267180 (rooted), A379439 (on orientable surface).