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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 17 |
| 5 | 50 |
| 6 | 147 |
| 7 | 434 |
| 8 | 1282 |
| 9 | 3789 |
| 10 | 11200 |
| 11 | 33109 |
| 12 | 97878 |
| 13 | 289354 |
| 14 | 855413 |
| 15 | 2528850 |
| 16 | 7476023 |
| 17 | 22101326 |
| 18 | 65338038 |
| 19 | 193158521 |
| 20 | 571033600 |
| 21 | 1688143881 |
| 22 | 4990651642 |
| 23 | 14753839486 |
| 24 | 43616704857 |
| 25 | 128943855250 |
| 26 | 381196100507 |
| 27 | 1126928202714 |
| 28 | 3331532438042 |
| 29 | 9848993360069 |
[0,1,2,6,17,50,147,434,1282,3789,11200,33109, 97878,289354,855413,2528850,7476023,22101326, 65338038,193158521,571033600,1688143881, 4990651642,14753839486,43616704857,128943855250, 381196100507,1126928202714,3331532438042, 9848993360069] |