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A274970
Number of 2-stack pushall sortable permutations of length n.
1
1, 1, 2, 6, 24, 120, 698, 4393, 28551, 187403, 1231517, 8080058, 52905865, 345820994
OFFSET
0,3
COMMENTS
A 2-stack pushall sortable permutation is one that can be sorted by two stacks in series by pushing all elements to the stacks before writing any element to the output.
A permutation of length n is 2-stack pushall sortable if and only if it can be sorted by a sequence of 3n operations represented by a pushall stack word of length 3n.
LINKS
Adeline Pierrot and Dominique Rossin, 2-stack pushall sortable permutations, arXiv:1303.4376 [cs.DM], 2013.
CROSSREFS
Cf. A263929 (permutations sortable with two stacks in series).
Cf. A274969 (pushall stack words of length 3n).
Sequence in context: A068200 A189847 A189284 * A177525 A177532 A242573
KEYWORD
nonn,more
AUTHOR
David Bevan, Jul 13 2016
EXTENSIONS
a(11)-a(13) from Bert Dobbelaere, Dec 26 2018
STATUS
approved