%I
%S 0,1,0,2,1,0,1,3,3,2,1,1,2,3,2,6,5,5,4,2,3,2,1,3,3,4,4,6,
%T 7,6,7,9,10,9,10,10,9,8,9,5,4,5,4,2,2,1,0,8,8,8,7,9,10,
%U 10,9,13,12,13,14,12,13,14,14,18,19,20,19,17,18,19,18,18,17,16,16,14,15
%N Det(M_n) where M_n is the n X n matrix m(i,j)=1 if floor(i/j) is even, 0 otherwise.
%C Det(Q_n) = 1 if Q_n denotes the n X n matrix defined by: m(i,j)=1 if floor(i/j) is odd, 0 otherwise, since this matrix is triangular with 1's on the main diagonal.
%o (PARI) for(n=1,70,print1(matdet(matrix(n,n,i,j,if((1)^(sigma(i+j))+1,1,0))),","))
%K easy,sign
%O 1,4
%A _Benoit Cloitre_, May 30 2002
