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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 105 |
| 5 | 430 |
| 6 | 1917 |
| 7 | 8344 |
| 8 | 38339 |
| 9 | 172896 |
| 10 | 808947 |
| 11 | 3725645 |
| 12 | 17647275 |
| 13 | 82496002 |
| 14 | 394115323 |
| 15 | 1862212671 |
| 16 | 8953469157 |
| 17 | 42647136320 |
| 18 | 206057059233 |
| 19 | 987669413703 |
| 20 | 4790583308431 |
| 21 | 23076758351160 |
| 22 | 112282290880467 |
| 23 | 543068170841868 |
| 24 | 2649172135026177 |
| 25 | 12855938931981320 |
| 26 | 62848396027216011 |
| 27 | 305844516598799957 |
[1,2,7,25,105,430,1917,8344,38339,172896,808947, 3725645,17647275,82496002,394115323,1862212671, 8953469157,42647136320,206057059233,987669413703, 4790583308431,23076758351160,112282290880467, 543068170841868,2649172135026177, 12855938931981320,62848396027216011, 305844516598799957] |