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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 26 |
| 6 | 104 |
| 7 | 436 |
| 8 | 1894 |
| 9 | 8444 |
| 10 | 38418 |
| 11 | 177656 |
| 12 | 832548 |
| 13 | 3945156 |
| 14 | 18871524 |
| 15 | 91003360 |
| 16 | 441927367 |
| 17 | 2159282462 |
| 18 | 10607708284 |
| 19 | 52363342484 |
| 20 | 259601860898 |
| 21 | 1292041756732 |
| 22 | 6453179670344 |
| 23 | 32334136480656 |
| 24 | 162487089008766 |
[1,1,2,7,26,104,436,1894,8444,38418,177656,832548, 3945156,18871524,91003360,441927367,2159282462, 10607708284,52363342484,259601860898, 1292041756732,6453179670344,32334136480656, 162487089008766] |