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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 1 |
| 4 | 19 |
| 5 | 43 |
| 6 | 461 |
| 7 | 2350 |
| 8 | 22940 |
| 9 | 185313 |
| 10 | 1969105 |
| 11 | 20981585 |
| 12 | 255992617 |
| 13 | 3300259584 |
| 14 | 46394533498 |
| 15 | 694535043925 |
| 16 | 11123040844947 |
| 17 | 189008829494295 |
| 18 | 3402841007703469 |
| 19 | 64648146404160854 |
| 20 | 1293014652241452452 |
| 21 | 27152832827254344741 |
| 22 | 597366828915334031625 |
[1,0,2,1,19,43,461,2350,22940,185313,1969105, 20981585,255992617,3300259584,46394533498, 694535043925,11123040844947,189008829494295, 3402841007703469,64648146404160854, 1293014652241452452,27152832827254344741, 597366828915334031625] |