OFFSET
1,2
FORMULA
Sum_{k, 1<=k<=n}T(n,k)=A003462(n)=(3^n-1)/2.
EXAMPLE
Triangle begins:
1;
2, 2;
3, 7, 3;
4, 16, 16, 4;
5, 30, 51, 30, 5;
6, 50, 126, 126, 50, 6;
7, 77, 266, 393, 266, 77, 7;
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Oct 30 2006
STATUS
approved