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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 31 |
| 3 | 244 |
| 4 | 2012 |
| 5 | 16831 |
| 6 | 142224 |
| 7 | 1212521 |
| 8 | 10412937 |
| 9 | 89964007 |
| 10 | 781192156 |
| 11 | 6812648578 |
| 12 | 59632654665 |
| 13 | 523659800584 |
| 14 | 4611408084221 |
| 15 | 40708677441051 |
| 16 | 360148330033068 |
| 17 | 3192319968308509 |
| 18 | 28344332639409466 |
| 19 | 252044515540416543 |
| 20 | 2244223537121190033 |
| 21 | 20006367211775121313 |
[0,31,244,2012,16831,142224,1212521,10412937, 89964007,781192156,6812648578,59632654665, 523659800584,4611408084221,40708677441051, 360148330033068,3192319968308509, 28344332639409466,252044515540416543, 2244223537121190033,20006367211775121313] |