%I A156826
%S A156826 1,2,1,3,1,1,4,1,0,1,5,2,1,0,1,6,2,1,0,0,1,7,3,1,1,0,0,1,8,3,
%T A156826 2,1,0,0,0,1,9,4,2,1,1,0,0,0,1,10,4,2,1,1,0,0,0,0,1,11,5,3,2,
%U A156826 1,1,0,0,0,0,1,12,5,3,2,1,1,0,0,0,0,0,1,13,6,3,2,1,1,1,0,0
%V A156826 1,2,-1,3,1,-1,4,-1,0,-1,5,2,1,0,-1,6,-2,-1,0,0,-1,7,3,-1,1,0,0,-1,8,-3,
%W A156826 2,-1,0,0,0,-1,9,4,-2,-1,1,0,0,0,-1,10,-4,-2,-1,-1,0,0,0,0,-1,11,5,3,2,
%X A156826 -1,1,0,0,0,0,-1,12,-5,-3,-2,-1,-1,0,0,0,0,0,-1,13,6,-3,-2,-1,-1,1,0,0
%N A156826 Square array read by anti diagonals up.
%C A156826 This square array is the same as A126988 except that the first row is 
               A153881.
%C A156826 Replace the zeros with -n/k. That is, the fraction of the row index divided 
               by the column index with a negative sign. Then swap the element in 
               the lower right corner with the element in the upper right corner 
               and calculate the determinant. The result appears to be sequence 
               A156827.
%e A156826 Table begins:
%e A156826 1.-1.-1.-1.-1.-1.-1.-1.-1.-1.-1.-1.-1
%e A156826 2..1..0..0..0..0..0..0..0..0..0..0..0
%e A156826 3..0..1..0..0..0..0..0..0..0..0..0..0
%e A156826 4..2..0..1..0..0..0..0..0..0..0..0..0
%e A156826 5..0..0..0..1..0..0..0..0..0..0..0..0
%e A156826 6..3..2..0..0..1..0..0..0..0..0..0..0
%e A156826 7..0..0..0..0..0..1..0..0..0..0..0..0
%e A156826 8..4..0..2..0..0..0..1..0..0..0..0..0
%e A156826 9..0..3..0..0..0..0..0..1..0..0..0..0
%e A156826 10.5..0..0..2..0..0..0..0..1..0..0..0
%e A156826 11.0..0..0..0..0..0..0..0..0..1..0..0
%e A156826 12.6..4..3..0..2..0..0..0..0..0..1..0
%e A156826 13.0..0..0..0..0..0..0..0..0..0..0..1
%o A156826 (Other) (Excel cell formula) =rounddown(if(mod(row();column())=0;row()/
               column();-row()/column())*if(row()=1;column();1);0)
%o A156826 (Excel cell formula) with fractions: =if(mod(row();column())=0;row()/
               column();-row()/column())*if(row()=1;column();1)
%Y A156826 Cf. A126988, A153881, A156827.
%Y A156826 Sequence in context: A006346 A088742 A144220 this_sequence A130296 A126705 
               A113924
%Y A156826 Adjacent sequences: A156823 A156824 A156825 this_sequence A156827 A156828 
               A156829
%K A156826 sign,tabl
%O A156826 1,2
%A A156826 Mats Granvik (mats.granvik(AT)abo.fi), Feb 16 2009