OFFSET
0,2
COMMENTS
LINKS
Alois P. Heinz, Rows n = 0..150, flattened
FORMULA
G.f.: (1+z-tz)/(1-3z-3z^2-tz+3tz^2).
EXAMPLE
T(4,2) = 6 because we have 0001, 0002, 0003, 1000, 2000 and 3000.
Triangle starts:
1;
4;
15, 1;
57, 6, 1;
216, 33, 6, 1;
819, 162, 36, 6, 1;
MAPLE
G:=(1+z-t*z)/(1-3*z-3*z^2-t*z+3*t*z^2): Gser:=simplify(series(G, z=0, 14)): for n from 0 to 11 do P[n]:=sort(coeff(Gser, z, n)) od: 1; for n from 1 to 11 do seq(coeff(P[n], t, j), j=0..n-1) od; # yields sequence in triangular form
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Emeric Deutsch, Feb 27 2007
STATUS
approved