OFFSET
0,2
COMMENTS
FORMULA
Number triangle T(n,k)=sum{j=0..n-k, C(n-j,k)C(n+k,j)}
T(n,k) = 3*T(n-1,k) + T(n-1,k-1) - 2*T(n-2,k), T(0,0) = T(1,1) = 1, T(1,0) = 2, T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Jan 17 2014
EXAMPLE
Triangle begins
1,
2, 1,
4, 5, 1,
8, 17, 8, 1,
16, 49, 39, 11, 1,
32, 129, 150, 70, 14, 1
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Oct 22 2006
STATUS
approved