OFFSET
0,4
COMMENTS
Triangle T(n,k), 0<=k<=n, read by rows, given by [ -1, -1, -3, -4, -7, -9, -13, -16, -21, ...] DELTA [1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, ...] where DELTA is the operator defined in A084938; see A004652 : 0, 1, 1, 3, 4, 7, 9, 13, ... - Philippe Deléham, Sep 26 2005
EXAMPLE
Rows begin:
1;
-1,1;
2,-3,1;
-7,12,-6,1;
41,-73,41,-10,1;
-376,675,-390,105,-15,1;
5033,-9048,5256,-1446,225,-21,1;
-92821,166901,-97034,26796,-4242,427,-28,1;
2257166,-4058703,2359939,-652054,103515,-10570,742,-36,1; ...
PROG
(PARI) T(n, k)=if(n<k || k<0, 0, ((matrix(n+2, n+2, m, j, if(m && gt; =j, polcoeff((1+x+x^2)^(m-1)+O(x^(2*j)), 2*j-2))))^-1)[n+1, k+1])
CROSSREFS
KEYWORD
sign,tabl
AUTHOR
Paul D. Hanna, Feb 26 2005
STATUS
approved