Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having nonzero determinant, with rows and columns of the latter in lexicographically nondecreasing order.
A227556
Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having nonzero determinant, with rows and columns of the latter in lexicographically nondecreasing order.
Terms
- a(0) =11a(1) =81a(2) =585a(3) =3939a(4) =23940a(5) =130231a(6) =635595a(7) =2807533a(8) =11342619a(9) =42338997a(10) =147335893a(11) =481696118a(12) =1489318226a(13) =4378976416a(14) =12302356074a(15) =33158604442a(16) =86042468013a(17) =215601894342a(18) =523073738362
External references
- oeis: A227556