OFFSET
0,7
FORMULA
Riordan array ((1-2x)/(1-x)^2,x(1-2x)/(1-x)^2); Number triangle T(n,k)=sum{j=0..k+1, C(k+1,j)C(n-j+k+1,2k+1)(-2)^j};
EXAMPLE
Triangle begins
1,
0, 1,
-1, 0, 1,
-2, -2, 0, 1,
-3, -4, -3, 0, 1,
-4, -5, -6, -4, 0, 1,
-5, -4, -6, -8, -5, 0, 1,
-6, 0, 0, -6, -10, -6, 0, 1
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Oct 30 2006
STATUS
approved