%I A128174
%S A128174 1,0,1,1,0,1,0,1,0,1,1,0,1,0,1,0,1,0,1,0,1,1,0,1,0,1,0,1,0,1,0,1,0,1,0,
%T A128174 1,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1
%N A128174 Transform, (1,0,1,...) in every column.
%C A128174 Inverse of the triangle = a tridiagonal matrix with (1,1,1...) in the 
               superdiagonal, (0,0,0,...) in the main diagonal and (-1,-1,-1,...) 
               in the subdiagonal.
%C A128174 Riordan array (1/(1-x^2),x) with inverse (1-x^2,x). [From Paul Barry 
               (pbarry(AT)wit.ie), Sep 10 2008]
%F A128174 A lower triangular matrix transform, (1, 0, 1,...) in every column; n 
               terms of (1, 0, 1,...) in odd rows; n terms of (0, 1, 0,...) in even 
               rows.
%F A128174 T(n,k)=[k<=n]*(1+(-1)^(n-k))/2; [From Paul Barry (pbarry(AT)wit.ie), 
               Sep 10 2008]
%F A128174 Row sum: sum_{k=1..n} T(n,k) = A004526(n+1). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               May 29 2009]
%e A128174 First few rows of the triangle are:
%e A128174 1;
%e A128174 0, 1;
%e A128174 1, 0, 1;
%e A128174 0, 1, 0, 1;
%e A128174 1, 0, 1, 0, 1;
%e A128174 ...
%Y A128174 Sequence in context: A129686 A104974 A024711 this_sequence A096055 A125144 
               A115198
%Y A128174 Adjacent sequences: A128171 A128172 A128173 this_sequence A128175 A128176 
               A128177
%K A128174 nonn,tabl
%O A128174 1,1
%A A128174 Gary W. Adamson (qntmpkt(AT)yahoo.com), Feb 17 2007