OFFSET
0,4
COMMENTS
EXAMPLE
Triangle begins:
1;
-1,1;
-3,-2,1;
-21,-7,-3,1;
-219,-53,-13,-4,1;
-2973,-583,-115,-21,-5,1;
-49323,-8249,-1437,-217,-31,-6,1;
-964173,-141655,-22715,-3101,-369,-43,-7,1; ...
PROG
(PARI) {T(n, k)=local(L, N, M=matrix(n+1, n+1, m, j, if(m>=j, if(m==j, 1, if(m==j+1, -3*j, polcoeff(1/sum(i=0, m-j, prod(r=0, i-1, 3*r+1)*x^i)+O(x^m), m-j)))))^-1); L=sum(i=1, #M, (M^0-M)^i/i)/3; N=sum(i=0, #L, L^i/i!); return(if(n<0, 0, N[n+1, k+1]))}
CROSSREFS
KEYWORD
sign,tabl
AUTHOR
Paul D. Hanna, May 30 2005
STATUS
approved