OFFSET
0,1
FORMULA
Number triangle T(n, k)=if(n=k, 1, 0) OR if(n=2k+1, 1, 0).
EXAMPLE
Triangle begins
1;
1, 1;
0, 0, 1;
0, 1, 0, 1;
0, 0, 0, 0, 1;
0, 0, 1, 0, 0, 1;
0, 0, 0, 0, 0, 0, 1;
0, 0, 0, 1, 0, 0, 0, 1;
0, 0, 0, 0, 0, 0, 0, 0, 1;
0, 0, 0, 0, 1, 0, 0, 0, 0, 1;
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Jan 21 2006
STATUS
approved