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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 55 |
| 4 | 540 |
| 5 | 5341 |
| 6 | 52866 |
| 7 | 523315 |
| 8 | 5180280 |
| 9 | 51279481 |
| 10 | 507614526 |
| 11 | 5024865775 |
| 12 | 49741043220 |
| 13 | 492385566421 |
| 14 | 4874114620986 |
| 15 | 48248760643435 |
| 16 | 477613491813360 |
| 17 | 4727886157490161 |
| 18 | 46801248083088246 |
| 19 | 463284594673392295 |
| 20 | 4586044698650834700 |
| 21 | 45397162391834954701 |
[1,6,55,540,5341,52866,523315,5180280,51279481, 507614526,5024865775,49741043220,492385566421, 4874114620986,48248760643435,477613491813360, 4727886157490161,46801248083088246, 463284594673392295,4586044698650834700, 45397162391834954701] |