OFFSET
0,8
FORMULA
T(n,n) = 1 for n >= 0, and T(n,n-1) = 1 - n for n > 0, and T(n,n-2) = 1 - n for n > 1, and T(n,k) = 0 if n < 0 or k < 0 or n < k or n > k+2.
G.f.: Sum_{n>=0, k=0..n} T(n,k) * x^k * t^n = (1 + t) * (1 - (1 + x) * t) / (1 - x * t)^2.
Alt. row sums equal (-1)^n for n >= 0.
EXAMPLE
The triangle T(n,k) for 0 <= k <= n starts:
n\k : 0 1 2 3 4 5 6 7 8 9
======================================================
0 : 1
1 : 0 1
2 : -1 -1 1
3 : 0 -2 -2 1
4 : 0 0 -3 -3 1
5 : 0 0 0 -4 -4 1
6 : 0 0 0 0 -5 -5 1
7 : 0 0 0 0 0 -6 -6 1
8 : 0 0 0 0 0 0 -7 -7 1
9 : 0 0 0 0 0 0 0 -8 -8 1
etc.
CROSSREFS
KEYWORD
AUTHOR
Werner Schulte, Apr 13 2022
STATUS
approved