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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 18 |
| 4 | 94 |
| 5 | 611 |
| 6 | 4381 |
| 7 | 35834 |
| 8 | 326662 |
| 9 | 3301193 |
| 10 | 36611767 |
| 11 | 442379438 |
| 12 | 5784595282 |
| 13 | 81393560783 |
| 14 | 1226280162097 |
| 15 | 19696507698878 |
| 16 | 335990910075202 |
| 17 | 6066382761193373 |
| 18 | 115578717461844067 |
| 19 | 2317323290060066858 |
[0,1,3,18,94,611,4381,35834,326662,3301193, 36611767,442379438,5784595282,81393560783, 1226280162097,19696507698878,335990910075202, 6066382761193373,115578717461844067, 2317323290060066858] |