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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 35 |
| 4 | 136 |
| 5 | 531 |
| 6 | 2071 |
| 7 | 8078 |
| 8 | 31509 |
| 9 | 122903 |
| 10 | 479392 |
| 11 | 1869903 |
| 12 | 7293691 |
| 13 | 28449566 |
| 14 | 110969577 |
| 15 | 432844811 |
| 16 | 1688342296 |
| 17 | 6585500475 |
| 18 | 25687217935 |
| 19 | 100194839822 |
| 20 | 390817174221 |
| 21 | 1524410477999 |
| 22 | 5946072636304 |
| 23 | 23193083691351 |
| 24 | 90466289938963 |
| 25 | 352870266163550 |
[1,2,9,35,136,531,2071,8078,31509,122903,479392, 1869903,7293691,28449566,110969577,432844811, 1688342296,6585500475,25687217935,100194839822, 390817174221,1524410477999,5946072636304, 23193083691351,90466289938963,352870266163550] |