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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 42 |
| 3 | 822 |
| 4 | 18708 |
| 5 | 464115 |
| 6 | 12175368 |
| 7 | 332156784 |
| 8 | 9328004700 |
| 9 | 267870927324 |
| 10 | 7829893576878 |
| 11 | 232189300430454 |
| 12 | 6968123350684692 |
| 13 | 211232335919261178 |
| 14 | 6458598626291716128 |
| 15 | 198949096401788859636 |
| 16 | 6168233789851179030684 |
| 17 | 192334850789654814053700 |
| 18 | 6027727888877572168027368 |
[1,3,42,822,18708,464115,12175368,332156784, 9328004700,267870927324,7829893576878, 232189300430454,6968123350684692, 211232335919261178,6458598626291716128, 198949096401788859636,6168233789851179030684, 192334850789654814053700, 6027727888877572168027368] |