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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 18 |
| 2 | 234 |
| 3 | 2682 |
| 4 | 34746 |
| 5 | 459138 |
| 6 | 6145542 |
| 7 | 82693062 |
| 8 | 1115442522 |
| 9 | 15062655582 |
| 10 | 203502787774 |
| 11 | 2750016143882 |
| 12 | 37165774777998 |
| 13 | 502308390521358 |
| 14 | 6789007978120728 |
| 15 | 91758451965134532 |
| 16 | 1240188134759212874 |
[1,18,234,2682,34746,459138,6145542,82693062, 1115442522,15062655582,203502787774,2750016143882, 37165774777998,502308390521358,6789007978120728, 91758451965134532,1240188134759212874] |