%I A115952
%S A115952 1,1,1,1,0,1,0,0,1,1,0,1,0,0,1,0,0,0,0,1,1,0,0,1,0,0,0,1,0,0,0,0,0,0,1,
               1,0,0,0,
%T A115952 1,0,0,0,0,1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,
               0,0,1,1,0,0,
%U A115952 0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1
%V A115952 1,-1,1,-1,0,1,0,0,-1,1,0,-1,0,0,1,0,0,0,0,-1,1,0,0,-1,0,0,0,1,0,0,0,0,
               0,0,-1,1,0,0,0,
%W A115952 -1,0,0,0,0,1,0,0,0,0,0,0,0,0,-1,1,0,0,0,0,-1,0,0,0,0,0,1,0,0,0,0,0,0,
               0,0,0,0,-1,1,0,0,
%X A115952 0,0,0,-1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,-1,1,0,0,0,0,0,0,-1
%N A115952 Expansion of (1-x+x*y)/(1-x^2*y^2)-x^2/(1-x^2*y).
%C A115952 Row sums are A000007. Diagonal sums are A115953. Inverse is A115954.
%F A115952 Number triangle T(n,k)=if(n=k,1,0) OR if(n=2k+2,-1,0) OR if(n=k+1,-(1+(-1)^k)/
               2,0).
%e A115952 Triangle begins
%e A115952 1,
%e A115952 -1, 1,
%e A115952 -1, 0, 1,
%e A115952 0, 0, -1, 1,
%e A115952 0, -1, 0, 0, 1,
%e A115952 0, 0, 0, 0, -1, 1,
%e A115952 0, 0, -1, 0, 0, 0, 1,
%e A115952 0, 0, 0, 0, 0, 0, -1, 1,
%e A115952 0, 0, 0, -1, 0, 0, 0, 0, 1,
%e A115952 0, 0, 0, 0, 0, 0, 0, 0, -1, 1,
%e A115952 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 1,
%e A115952 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1,
%e A115952 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 1,
%e A115952 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1,
%e A115952 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 1,
%e A115952 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1
%Y A115952 Cf. A115524.
%Y A115952 Sequence in context: A156254 A010056 A155898 this_sequence A115524 A117198 
               A054525
%Y A115952 Adjacent sequences: A115949 A115950 A115951 this_sequence A115953 A115954 
               A115955
%K A115952 easy,sign,tabl
%O A115952 0,1
%A A115952 Paul Barry (pbarry(AT)wit.ie), Feb 02 2006