OFFSET
0,2
COMMENTS
FORMULA
T(n,0) = 3*T(n-1,0), T(n,k) = T(n-1,k-1) + 3*T(n-1,k) + T(n-1,k+1) for k>0, T(n,k) = 0 if k<0 or if k>n, T(0,0) = 1.
EXAMPLE
Triangle begins:
1;
3, 1;
9, 6, 1;
27, 28, 9, 1;
81, 120, 56, 12, 1;
243, 497, 300, 93, 15, 1;
729, 2034, 1490, 594, 139, 18, 1
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Jan 25 2014
STATUS
approved