| DATA
|
4, 28, 132, 671, 3444, 17558, 89613, 457188, 2333009, 11905494, 60751194, 310004765, 1581914211, 8072288131, 41191772847, 210195946958, 1072600980393, 5473335132061, 27929675517731, 142521288635027, 727266512789731
|
| EXAMPLE
|
Some solutions for n=7
..0..0..0. .0..1..0. .0..0..1. .0..0..0. .1..1..0. .0..0..0. .0..1..1
..1..1..1. .0..1..0. .0..1..0. .1..0..1. .0..1..0. .0..1..1. .1..0..0
..0..0..1. .0..1..1. .0..0..0. .1..0..1. .0..1..0. .0..1..0. .0..1..0
..1..1..0. .0..0..1. .1..1..0. .1..1..0. .0..0..1. .1..1..0. .1..1..1
..0..0..0. .0..0..0. .1..0..1. .0..0..0. .1..1..1. .0..0..0. .0..1..0
..1..1..1. .0..0..1. .0..0..1. .0..1..0. .1..0..0. .1..0..0. .1..1..0
..0..0..1. .0..1..0. .0..1..0. .0..1..0. .0..0..0. .1..1..0. .0..0..0
|