OFFSET
1,5
COMMENTS
See Barnabei et al. (2012) for precise definition.
LINKS
M. Barnabei, F. Bonetti and M. Silimbani, Two permutation classes related to the Bubble Sort operator, Electronic Journal of Combinatorics 19(3) (2012), #P25. See Theorem 6.
EXAMPLE
Triangle begins:
1
1 1
1 4 1
1 10 9
1 20 41 6
1 35 133 61 2
1 56 350 336 49
1 84 798 1336 465 20
1 120 1638 4300 2789 380 4
...
PROG
(PARI) rows(nn) = {my(pol = Pol((1 - 3*x + 3*x^2 - 3*x^2*y - x^3 + 2*x^3*y - x^3*y^2)/(1 - 4*x + 6*x^2 - 4*x^2*y - 4*x^3 + 6*x^3*y - 2*x^3*y^2 + x^4 - 2*x^4*y + x^4*y^2) + O(x^nn))); for (i=1, poldegree(pol, x), ypol = polcoeff(pol, i, x); for (j=0, poldegree(ypol, y), print1(polcoeff(ypol, j, y), ", "); ); print(); ); } \\ Michel Marcus, Jul 23 2014
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
N. J. A. Sloane, Dec 25 2012
EXTENSIONS
More terms from Michel Marcus, Jul 23 2014
Keyword set to tabf by Michel Marcus, Jul 23 2014
STATUS
approved