Mitchel T. Keller has authored 3 sequences.
A293501
Number of unlabeled semiorders on n points and having dimension 3.
Original entry on oeis.org
3, 40, 318, 1974, 10603, 51894, 238413, 1047440, 4454826, 18496217, 75416600, 303287250, 1206781482, 4762466651, 18674965709, 72866587238, 283217927396, 1097537249485, 4243554109115, 16379413110981, 63142882465324, 243203630272390
Offset: 7
A293499
Number of unlabeled hereditary semiorders on n points.
Original entry on oeis.org
1, 2, 5, 14, 42, 132, 428, 1415, 4730, 15901, 53593, 180809, 610157, 2058962, 6947145, 23437854, 79067006, 266717300, 899693960, 3034814143, 10236853534, 34530252629, 116475001757, 392885252033
Offset: 1
- M. T. Keller and S. J. Young, Hereditary semiorders and enumeration of semiorders by dimension. Preprint (2017).
- M. Bousquet-Mélou, A. Claesson, M. Dukes, and S. Kitaev, (2+2)-free posets, ascent sequences and pattern avoiding permutations, J. Combin. Theory Ser. A 117, 7 (2010), 884-909.
- Mitchel T. Keller, Stephen J. Young, Hereditary Semiorders and Enumeration of Semiorders by Dimension, arXiv:1801.00501 [math.CO], (2018)
- Index entries for linear recurrences with constant coefficients, signature (8,-23,29,-14,1).
-
CoefficientList[ Series[(-1 +6x -12x^2 +9x^3 -x^4)/(-1 +8x -23x^2 +29x^3 -14x^4 +x^5), {x, 0, 26}], x] (* or *)
LinearRecurrence[{8, -23, 29, -14, 1}, {1, 2, 5, 14, 42}, 27] (* Robert G. Wilson v, Jan 07 2018 *)
A293498
Number of unlabeled semiorders on n points and having dimension at most 2.
Original entry on oeis.org
1, 2, 5, 14, 42, 132, 426, 1390, 4544, 14822, 48183, 156118, 504487, 1627000, 5240019, 16861453, 54228190, 174351450, 560481708, 1801653769, 5791301311, 18615976402, 59841686254, 192366897839, 618392292337
Offset: 1
- Mitchel T. Keller, Stephen J. Young, Hereditary Semiorders and Enumeration of Semiorders by Dimension, arXiv:1801.00501 [math.CO], 2018.
- Index entries for linear recurrences with constant coefficients, signature (12,-61,172,-294,311,-197,66,-7).
Comments