OFFSET
1,5
COMMENTS
It appears that no recurrence or g.f. is known. - N. J. A. Sloane, Oct 13 2015
LINKS
FindStat - Combinatorial Statistic Finder, The number of stack-sorts needed to sort a permutation
Julian West, Permutations with forbidden subsequences; and, stack-sortable permutations, Ph.D. thesis, Massachusetts Institute of Technology, Dept. of Mathematics, 1990. See p. 76.
FORMULA
T(n,0) = 1, T(n,1) = A000108(n) - 1. - Joerg Arndt, Sep 27 2015
EXAMPLE
Triangle begins:
1;
1, 1;
1, 4, 1;
1, 13, 8, 2;
1, 41, 49, 23, 6;
1, 131, 276, 198, 90, 24;
1, 428, 1509, 1556, 982, 444, 120;
1, 1429, 8184, 11812, 9678, 5856, 2640, 720;
1, 4861, 44473, 88566, 91959, 68820, 40800, 18360, 5040;
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Christian Stump, Sep 24 2015
EXTENSIONS
Definition edited by N. J. A. Sloane, Oct 13 2015
More terms from Christian Stump, Oct 19 2015
Rows n=7-10 from Julian West's thesis added by Alois P. Heinz, Jun 27 2023
STATUS
approved