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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 11 |
| 3 | 45 |
| 4 | 915 |
| 5 | 4623 |
| 6 | 48831 |
| 7 | 261573 |
| 8 | 11394435 |
| 9 | 62705435 |
| 10 | 696466693 |
| 11 | 3895633963 |
| 12 | 87686110551 |
| 13 | 495923797275 |
| 14 | 5633839691175 |
| 15 | 32120544847605 |
| 16 | 2939641341968355 |
| 17 | 16862789923200915 |
| 18 | 193953498934510825 |
| 19 | 1117946167892824975 |
[1,1,11,45,915,4623,48831,261573,11394435, 62705435,696466693,3895633963,87686110551, 495923797275,5633839691175,32120544847605, 2939641341968355,16862789923200915, 193953498934510825,1117946167892824975] |