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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 3 |
| 4 | 148 |
| 5 | 905 |
| 6 | 40506 |
| 7 | 542437 |
| 8 | 25080392 |
| 9 | 562677201 |
| 10 | 28058678110 |
| 11 | 908452740701 |
| 12 | 49777760550684 |
| 13 | 2120072013408505 |
| 14 | 128583516119137730 |
| 15 | 6778703037793746165 |
| 16 | 455574282215526201616 |
| 17 | 28520235381763443992993 |
| 18 | 2118889776612629769160518 |
[1,0,2,3,148,905,40506,542437,25080392,562677201, 28058678110,908452740701,49777760550684, 2120072013408505,128583516119137730, 6778703037793746165,455574282215526201616, 28520235381763443992993,2118889776612629769160518] |