%I #5 Mar 30 2012 18:39:23

%S 0,-1,-1,2,0,-2,-9,9,-13,-40,52,16,3,3,-25,150,73,-119,435,-409,-1479,

%T -1526,2783,-1065,-7623,-6534,-2961,10905,-7625,-49205,114044,-160163,

%U -364571,849751,6638244,936704,-19925924,29919679,44801693,15691398,-78571565,78004083,152659515,-328585072

%N a(n)=det(M_n) where M_n is the n X n matrix m(i,j)=1 if sigma(i+j) is even, 0 otherwise.

%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