OFFSET
0,1
COMMENTS
Diagonal sums: A060576.
FORMULA
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A046698(n+1), A111286(n+1), A027327(n) for x= 0, 1, 2, 3 respectively.
G.f.: (1+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(2,1) = T(2,2) = 1, T(1,0) = T(2,0) = 0, T(n,k) = 0 if k < 0 or if k > n. - Philippe Deléham, Nov 09 2013
EXAMPLE
Triangle begins:
1;
0, 1;
0, 1, 1;
0, 0, 1, 1;
0, 0, 0, 1, 1;
0, 0, 0, 0, 1, 1; ...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Nov 02 2009
STATUS
approved