OFFSET
0,2
COMMENTS
A triangle having similar properties and complementary construction is the dual triangle A121437.
FORMULA
EXAMPLE
Triangle, A121336^-1, begins:
1;
-4, 1;
3, -6, 1;
-12, 9, -9, 1;
-117, -26, 26, -13, 1;
-1656, -216, -69, 63, -18, 1;
-28506, -3396, -294, -212, 132, -24, 1;
-578274, -63116, -5766, -124, -620, 248, -31, 1;
-13504179, -1365546, -116116, -8892, 1170, -1612, 429, -39, 1; ...
Triangle A121412 begins:
1;
1, 1;
3, 1, 1;
18, 4, 1, 1;
170, 30, 5, 1, 1; ...
1;
-9, 1;
18, -9, 1;
-12, 9, -9, 1; ...
1;
-13, 1;
52, -13, 1;
-52, 39, -13, 1;
-117, -26, 26, -13, 1; ...
PROG
(PARI) /* Matrix Inverse of A121336 */ {T(n, k)=local(M=matrix(n+1, n+1, r, c, if(r>=c, binomial(r*(r-1)/2+r-c+2, r-c)))); return((M^-1)[n+1, k+1])}
CROSSREFS
KEYWORD
sign,tabl
AUTHOR
Paul D. Hanna, Aug 29 2006
STATUS
approved