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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 22 |
| 3 | 116 |
| 4 | 806 |
| 5 | 4028 |
| 6 | 26876 |
| 7 | 132776 |
| 8 | 808710 |
| 9 | 4170604 |
| 10 | 23586836 |
| 11 | 120316888 |
| 12 | 673359196 |
| 13 | 3383189976 |
| 14 | 18228019512 |
| 15 | 92654842960 |
| 16 | 486382544838 |
| 17 | 2443171359820 |
| 18 | 12694346947492 |
| 19 | 63262412763896 |
| 20 | 323739858349684 |
| 21 | 1609270321201800 |
| 22 | 8117702067063368 |
| 23 | 40102791350319408 |
[1,2,22,116,806,4028,26876,132776,808710,4170604, 23586836,120316888,673359196,3383189976, 18228019512,92654842960,486382544838, 2443171359820,12694346947492,63262412763896, 323739858349684,1609270321201800,8117702067063368, 40102791350319408] |