OFFSET
0,2
COMMENTS
FORMULA
G.f.: [xy(1+x)(1+y)] / [(1-x)^3 * (1-y)^3 ]. - Ralf Stephan, Oct 27 2004
EXAMPLE
1; 4,4; 9,16,9; 16,36,36,16; ...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Douglas Stones (dssto1(AT)student.monash.edu.au), Sep 04 2004
STATUS
approved