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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 45 |
| 4 | 580 |
| 5 | 7105 |
| 6 | 170076 |
| 7 | 2654575 |
| 8 | 116426528 |
| 9 | 2386183761 |
| 10 | 209503380160 |
| 11 | 3455683548691 |
| 12 | 969334978024920 |
| 13 | 15164681616944353 |
| 14 | 6510178188269825720 |
| 15 | 223847763757748796975 |
| 16 | 81261936394687862700256 |
| 17 | 1581790511799886415713825 |
[1,1,6,45,580,7105,170076,2654575,116426528, 2386183761,209503380160,3455683548691, 969334978024920,15164681616944353, 6510178188269825720,223847763757748796975, 81261936394687862700256,1581790511799886415713825] |