OFFSET
0,2
LINKS
Robert Israel, Table of n, a(n) for n = 0..10009 (rows 0 to 140, flattened)
FORMULA
G.f. as triangle (conjectured): (1-x)*(1-x+x^2)/(1-x*y+3*x^2-x^3*y+x^4). - Robert Israel, Jul 07 2019
EXAMPLE
First few rows of the triangle are:
1;
-2, 1;
-1, -2, 1;
5, -3, -2, 1;
2, 9, -5, -2, 1;
-13, 9, 13, -7, -2, 1;
...
MAPLE
T:= Matrix(20, 20, (n, k) -> binomial(n-1, floor((n)/2 - (-1)^(n-k)*(k)/2)), shape=triangular[lower]):
A:= T^(-2):
seq(seq(A[i, k], k=1..i), i=1..20); # Robert Israel, Jul 07 2019
CROSSREFS
KEYWORD
tabl,sign
AUTHOR
Gary W. Adamson, Dec 17 2006
STATUS
approved