A167655 - OEIS

%I #7 Jan 22 2014 14:00:56

%S 1,-1,1,1,-2,1,0,2,-3,1,-1,0,4,-4,1,1,-3,-1,7,-5,1,0,4,-6,-4,11,-6,1,

%T -1,-1,11,-9,-10,16,-7,1,1,-4,-6,24,-10,-20,22,-8,1,0,6,-9,-21,44,-6,

%U -35,29,-9,1,-1,-2,21,-12,-55,70,7,-56,37,-10,1

%N Riordan array (1-u,u) where u=x/(1+x+x^2).

%C Inverse of Riordan array A167630. Row sums : A000007.

%F T(n,k) = T(n-1,k-1) - T(n-1,k) - T(n-2,k), T(0,0) = T(1,1) = T(2,0) = T(2,2) = 1, T(1,0) = -1, T(2,1) = -2, T(n,k) = 0 if k<0 or if k>n. - _Philippe Deléham_, Jan 22 2014

%e Triangle begins:

%e 1;

%e -1, 1;

%e 1, -2, 1;

%e 0, 2, -3, 1;

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

%e 1, -3, -1, 7, -5, 1;

%e 0, 4, -6, -4, 11, -6, 1;

%e -1, -1, 11, -9, -10, 16, -7, 1;

%e 1, -4, -6, 24, -10, -20, 22, -8, 1;

%e 0, 6, -9, -21, 44, -6, -35, 29, -9, 1;

%e -1, -2, 21, -12, -55, 70, 7, -56, 37, -10, 1;

%e ... _Philippe Deléham_, Jan 22 2014

%Y Cf. A000124

%K sign,tabl

%O 0,5

%A _Philippe Deléham_, Nov 08 2009