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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 53 |
| 4 | 242 |
| 5 | 1131 |
| 6 | 5375 |
| 7 | 25770 |
| 8 | 124613 |
| 9 | 606018 |
| 10 | 2959699 |
| 11 | 14507794 |
| 12 | 71303815 |
| 13 | 351256141 |
| 14 | 1733644863 |
| 15 | 8569727681 |
| 16 | 42418344280 |
| 17 | 210196707443 |
| 18 | 1042591974695 |
| 19 | 5175657001614 |
| 20 | 25711584348853 |
| 21 | 127810271426162 |
| 22 | 635686118474741 |
| 23 | 3163229223668441 |
| 24 | 15747294822922287 |
| 25 | 78423745649255033 |
[1,3,12,53,242,1131,5375,25770,124613,606018, 2959699,14507794,71303815,351256141,1733644863, 8569727681,42418344280,210196707443,1042591974695, 5175657001614,25711584348853,127810271426162, 635686118474741,3163229223668441, 15747294822922287,78423745649255033] |