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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 45 |
| 6 | 241 |
| 7 | 1428 |
| 8 | 9325 |
| 9 | 67035 |
| 10 | 524926 |
| 11 | 4429953 |
| 12 | 40010785 |
| 13 | 384853560 |
| 14 | 3925008361 |
| 15 | 42270555603 |
| 16 | 478998800290 |
| 17 | 5693742545445 |
| 18 | 70804642315921 |
| 19 | 918928774274028 |
| 20 | 12419848913448565 |
| 21 | 174467677050577515 |
| 22 | 2542777209440690806 |
| 23 | 38388037137038323353 |
[1,0,1,3,10,45,241,1428,9325,67035,524926,4429953, 40010785,384853560,3925008361,42270555603, 478998800290,5693742545445,70804642315921, 918928774274028,12419848913448565, 174467677050577515,2542777209440690806, 38388037137038323353] |