A263929 Number of permutations that are sortable with two stacks in series.

1, 1, 2, 6, 24, 120, 720, 5018, 39374, 337816, 3092691, 29659731, 294107811, 2988678546, 30935695794, 324832481490, 3450158410649, 36993206191004, 399827092167771, 4351269802153188

Offset: 0

Author

Joerg Arndt, Oct 30 2015

Keywords

• nonn

Links

• Andrew Elvey-Price, Anthony J Guttmann, Permutations sortable by two stacks in series, arXiv:1510.08663 [math.CO], (29-October-2015)