OFFSET
0,8
FORMULA
G.f.: x*y*(1+x+y)/((1-x-x^2)*(1-y-y^2)). [U coordinates]
EXAMPLE
0; 0,0; 0,1,0; 0,2,2,0; 0,3,3,3,0; 0,5,5,5,5,0; ...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
N. J. A. Sloane, Jun 01 2005
STATUS
approved