| A Parameterized Route to Exact Puzzles: Breaking the 2n-Barrier for Irredundance Recent countries visiting this post |  |
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| A Parameterized Route to Exact Puzzles: Breaking the 2n-Barrier for Irredundance Recent countries visiting this post | |
| 5 | United States |
| 1 | Germany |
| 1 | |
| 1 | Italy |
| 1 | Russian Federation |