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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 10 |
| 5 | 31 |
| 6 | 361 |
| 7 | 2164 |
| 8 | 32663 |
| 9 | 313121 |
| 10 | 6199024 |
| 11 | 86219497 |
| 12 | 2225685925 |
| 13 | 42396094690 |
| 14 | 1414152064833 |
| 15 | 35520966967269 |
| 16 | 1517860883350266 |
| 17 | 48936884016265947 |
| 18 | 2659543345912283917 |
| 19 | 107827798819822505332 |
| 20 | 7409614386025588874195 |
| 21 | 371626299919138199117981 |
[1,0,1,1,10,31,361,2164,32663,313121,6199024, 86219497,2225685925,42396094690,1414152064833, 35520966967269,1517860883350266,48936884016265947, 2659543345912283917,107827798819822505332, 7409614386025588874195,371626299919138199117981] |