A119302 - OEIS

%I #4 Mar 30 2012 18:59:15

%S 1,-3,1,0,-5,1,0,7,-7,1,0,-3,18,-9,1,0,0,-22,33,-11,1,0,0,13,-65,52,

%T -13,1,0,0,-3,75,-140,75,-15,1,0,0,0,-51,238,-255,102,-17,1,0,0,0,19,

%U -266,570,-418,133,-19,1,0,0,0,-3,196,-882,1155,-637,168,-21,1

%N Inverse of number triangle binomial(3n-k,n-k).

%C Row sums are A119303. Inverse of A119301.

%F Riordan array (1-3x,x(1-x)^2); Number triangle T(n,k)=(C(2k,n-k)+3*C(2k,n-k-1))(-1)^(n-k).

%e Triangle begins

%e 1,

%e -3, 1,

%e 0, -5, 1,

%e 0, 7, -7, 1,

%e 0, -3, 18, -9, 1,

%e 0, 0, -22, 33, -11, 1,

%e 0, 0, 13, -65, 52, -13, 1,

%e 0, 0, -3, 75, -140, 75, -15, 1

%K easy,sign,tabl

%O 0,2

%A _Paul Barry_, May 13 2006