A109970 - OEIS

%I #3 Mar 30 2012 18:59:08

%S 1,0,1,0,-2,1,0,1,-4,1,0,0,6,-6,1,0,0,-4,15,-8,1,0,0,1,-20,28,-10,1,0,

%T 0,0,15,-56,45,-12,1,0,0,0,-6,70,-120,66,-14,1,0,0,0,1,-56,210,-220,

%U 91,-16,1,0,0,0,0,28,-252,495,-364,120,-18,1

%N Riordan array (1,x(1-x)^2).

%C Row sums are A077954. Diagonal sums are (-1)^n*A094686(n). Matrix inverse is A109971.

%F G.f.: 1/(1-xy(1-x)^2); Number triangle T(n, k)=binomial(2k, n-k)*(-1)^(n-k).

%e Rows begin

%e 1;

%e 0,1;

%e 0,-2,1;

%e 0,1,-4,1;

%e 0,0,6,-6,1;

%e 0,0,-4,15,-8,1;

%e 0,0,1,-20,28,-10,1;

%e 0,0,0,15,-56,45,-12,1;

%K easy,sign,tabl

%O 0,5

%A _Paul Barry_, Jul 06 2005