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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 16 |
| 3 | 137 |
| 4 | 1216 |
| 5 | 11057 |
| 6 | 102229 |
| 7 | 956601 |
| 8 | 9032680 |
| 9 | 85893860 |
| 10 | 821402341 |
| 11 | 7891371303 |
| 12 | 76105710253 |
| 13 | 736364519399 |
| 14 | 7144586617597 |
| 15 | 69487754788517 |
| 16 | 677259385478616 |
| 17 | 6613163312601491 |
| 18 | 64681617534027028 |
| 19 | 633569272646345064 |
| 20 | 6214190349161222941 |
| 21 | 61023489213944162889 |
[1,2,16,137,1216,11057,102229,956601,9032680, 85893860,821402341,7891371303,76105710253, 736364519399,7144586617597,69487754788517, 677259385478616,6613163312601491, 64681617534027028,633569272646345064, 6214190349161222941,61023489213944162889] |