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Riordan array (1/(1+3x+2x^2),x/(1+3x+2x^2)).
0

%I #6 Jan 04 2014 19:49:18

%S 1,-3,1,7,-6,1,-15,23,-9,1,31,-72,48,-12,1,-63,201,-198,82,-15,1,127,

%T -522,699,-420,125,-18,1,-255,1291,-2223,1795,-765,177,-21,1,511,

%U -3084,6562,-6768,3840,-1260,238,-24,1,-1023,7181,-18324,23276,-16758,7266,-1932,308,-27,1,2047,-16398,49029,-74616,65870

%N Riordan array (1/(1+3x+2x^2),x/(1+3x+2x^2)).

%C Signed version of A110441. Factors as (1/(1+x),x/(1+x))*((1-x)/(1+x),x(1-x)/(1+x)), or inverse binomial transform of A080246. Inverse of little Schroeder number array A110440. Row sums are A108520. Diagonal sums are (-1)^n*A001906(n+1).

%F T(n,k)=-3*T(n-1,k)+T(n-1,k-1)-2*T(n-2,k), T(0,0)=1, T(n,k)=0 if k<0 or if k>n. - _Philippe Deléham_, Jan 04 2013

%e Triangle starts

%e 1;

%e -3,1;

%e 7,-6,1;

%e -15,23,-9,1;

%e 31,-72,48,-12,1;

%K easy,sign,tabl

%O 0,2

%A _Paul Barry_, Aug 18 2005