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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 22 |
| 5 | 150 |
| 6 | 1173 |
| 7 | 10148 |
| 8 | 94925 |
| 9 | 945972 |
| 10 | 9941558 |
| 11 | 109382042 |
| 12 | 1253180343 |
| 13 | 14889508598 |
| 14 | 182880186850 |
| 15 | 2316222358948 |
| 16 | 30188514546787 |
| 17 | 404233232273788 |
| 18 | 5553341502305868 |
| 19 | 78182001588059148 |
| 20 | 1126836634877469526 |
| 21 | 16612944202665079800 |
| 22 | 250345193073480290120 |
[1,1,4,22,150,1173,10148,94925,945972,9941558, 109382042,1253180343,14889508598,182880186850, 2316222358948,30188514546787,404233232273788, 5553341502305868,78182001588059148, 1126836634877469526,16612944202665079800, 250345193073480290120] |