OFFSET
0,2
FORMULA
G.f.: (1+2*x+2*x^2+x^2*y)/(1-x*y). - Philippe Deléham, Nov 09 2013
T(n,k) = T(n-1,k-1) for n>2, T(0,0) = T(1,1) = T(2,2) = 1, T(1,0) = T(2,0) = 2, T(2,1) = 3, T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Nov 09 2013
EXAMPLE
Triangle begins :
1 ;
2,1 ;
2,3,1 ;
0,2,3,1 ;
0,0,2,3,1 ;
0,0,0,2,3,1 ;
0,0,0,0,2,3,1 ; ...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Nov 09 2009
STATUS
approved