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 A113680 Riordan array ((1-x-2x^2)/(1-x),x). 2

%I

%S 1,0,1,-2,0,1,-2,-2,0,1,-2,-2,-2,0,1,-2,-2,-2,-2,0,1,-2,-2,-2,-2,-2,0,

%T 1,-2,-2,-2,-2,-2,-2,0,1,-2,-2,-2,-2,-2,-2,-2,0,1,-2,-2,-2,-2,-2,-2,

%U -2,-2,0,1,-2,-2,-2,-2,-2,-2,-2,-2,-2,0,1,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,0,1,-2,-2,-2,-2,-2,-2,-2,-2

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

%C Inverse of A113678. Sequence array of A113679. Row sums are 3-2n-2*0^n. Diagonal sums are 1-n.

%F Number triangle T(n, k)=if(k<=n, C(0, n-k)+2*C(1, n-k)-2, 0).

%e Triangle begins

%e 1;

%e 0, 1;

%e -2, 0, 1;

%e -2, -2, 0, 1;

%e -2, -2, -2, 0, 1;

%e -2, -2, -2, -2, 0, 1;

%K easy,sign,tabl

%O 0,4

%A _Paul Barry_, Nov 04 2005

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Last modified October 15 04:33 EDT 2019. Contains 328026 sequences. (Running on oeis4.)