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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 12 |
| 3 | 49 |
| 4 | 409 |
| 5 | 2596 |
| 6 | 18321 |
| 7 | 124177 |
| 8 | 854764 |
| 9 | 5849089 |
| 10 | 40115241 |
| 11 | 274888516 |
| 12 | 1884285217 |
| 13 | 12914634529 |
| 14 | 88519396044 |
| 15 | 606717892561 |
| 16 | 4158514347961 |
| 17 | 28502860300132 |
| 18 | 195361565985969 |
| 19 | 1339027949145649 |
| 20 | 9177834477168556 |
| 21 | 62905812346085281 |
| 22 | 431162854681140297 |
[1,1,12,49,409,2596,18321,124177,854764,5849089, 40115241,274888516,1884285217,12914634529, 88519396044,606717892561,4158514347961, 28502860300132,195361565985969,1339027949145649, 9177834477168556,62905812346085281, 431162854681140297] |