A115356 - OEIS

%I #3 Mar 30 2012 18:59:13

%S 1,1,1,0,0,1,0,1,0,1,0,0,0,0,1,0,0,1,0,0,1,0,0,0,0,0,0,1,0,0,0,1,0,0,

%T 0,1,0,0,0,0,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,

%U 0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,1

%N Matrix (1,x)+(x,x^2) in Riordan array notation.

%C Row sums are A000034. Diagonal sums are A115357. Inverse is A115358.

%F Number triangle T(n, k)=if(n=k, 1, 0) OR if(n=2k+1, 1, 0).

%e Triangle begins

%e 1;

%e 1, 1;

%e 0, 0, 1;

%e 0, 1, 0, 1;

%e 0, 0, 0, 0, 1;

%e 0, 0, 1, 0, 0, 1;

%e 0, 0, 0, 0, 0, 0, 1;

%e 0, 0, 0, 1, 0, 0, 0, 1;

%e 0, 0, 0, 0, 0, 0, 0, 0, 1;

%e 0, 0, 0, 0, 1, 0, 0, 0, 0, 1;

%K easy,nonn,tabl

%O 0,1

%A _Paul Barry_, Jan 21 2006