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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 66 |
| 4 | 504 |
| 5 | 4148 |
| 6 | 35794 |
| 7 | 319384 |
| 8 | 2922472 |
| 9 | 27273568 |
| 10 | 258591700 |
| 11 | 2483951402 |
| 12 | 24121423518 |
| 13 | 236417231844 |
| 14 | 2335648036770 |
| 15 | 23234567806722 |
| 16 | 232536604918010 |
| 17 | 2339766365713070 |
| 18 | 23655013692855212 |
| 19 | 240175288588925992 |
| 20 | 2447961627258995826 |
| 21 | 25037715732340569328 |
| 22 | 256899046844874628732 |
[1,2,10,66,504,4148,35794,319384,2922472,27273568, 258591700,2483951402,24121423518,236417231844, 2335648036770,23234567806722,232536604918010, 2339766365713070,23655013692855212, 240175288588925992,2447961627258995826, 25037715732340569328,256899046844874628732] |