OFFSET
1,3
COMMENTS
FORMULA
From Franklin T. Adams-Watters, Apr 12 2011: (Start)
T(n,k) = (2k - 1 + (-1)^(n-k)*(2n+1))/4.
|T(n,k)| = (2n+1 + (-1)^(n-k)*(2k-1))/4. (End)
EXAMPLE
Triangle begins:
1;
-1, 2;
2, -1, 3;
-2, 3, -1, 4;
3, -2, 4, -1, 5;
-3, 4, -2, 5, -1, 6;
4, -3, 5, -2, 6, -1, 7;
...
PROG
(PARI) T(n, k)=(2*k-1+(-1)^(n-k)*(2*n+1))/4 \\ Franklin T. Adams-Watters, Apr 12 2011
CROSSREFS
KEYWORD
tabl,sign
AUTHOR
Gary W. Adamson, Feb 17 2007
STATUS
approved