| DATA
|
0, 5, 50, 538, 3932, 32253, 238532, 1875212, 14222474, 110768815, 851356180, 6619388000, 51243150110, 398853561051, 3101596551513, 24188042117410, 188685917890136, 1474444397004861, 11529364760294089, 90260751863587788
|
| EXAMPLE
|
Some solutions for n=4
..1..0..1. .0..0..1. .0..1..0. .0..1..1. .1..0..0. .1..1..0. .0..1..1
..0..0..1. .1..1..0. .0..1..1. .0..0..0. .0..0..0. .1..1..0. .0..0..1
..1..0..0. .0..0..1. .0..1..0. .1..1..0. .1..0..1. .1..0..0. .0..0..1
..0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..0..0. .0..0..1. .1..0..0
|