Permutations sortable by two stacks in series

  title={Permutations sortable by two stacks in series},
  author={Andrew Elvey-Price and Anthony J. Guttmann},
We address the problem of the number of permutations that can be sorted by two stacks in series. We do this by first counting all such permutations of length less than 20 exactly, then using a numerical technique to obtain eleven further coefficients approximately. Analysing these coefficients by a variety of methods we conclude that the OGF behaves as S(z… CONTINUE READING