OFFSET
0,2
COMMENTS
Row n has floor(n/2) terms (n >= 2).
Row sums are the Catalan numbers (A000108).
FORMULA
EXAMPLE
Triangle starts:
1;
2;
5;
14;
40, 2;
116, 16;
344, 80, 5;
1040, 340, 50;
MAPLE
G:=1/2*(1-4*z^3*t^2-4*z^3-2*z^2*t+8*z^3*t-2*z+2*z^2*t^2-sqrt(1-8*z^3+4*z^2-4*z^2*t-4*z+8*z^3*t))/z^2/(2*z*t-t-2*z)^2: Gser:=simplify(series(G, z=0, 18)): for n from 0 to 14 do P[n]:=sort(coeff(Gser, z, n)) od: 1; 2; for n from 2 to 14 do seq(coeff(P[n], t, j), j=0..floor(n/2)-1) od; # yields sequence in triangular form
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Emeric Deutsch, Dec 25 2006, Aug 17 2008
STATUS
approved