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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 54 |
| 3 | 361 |
| 4 | 2420 |
| 5 | 16227 |
| 6 | 108802 |
| 7 | 729512 |
| 8 | 4891347 |
| 9 | 32796280 |
| 10 | 219897701 |
| 11 | 1474404984 |
| 12 | 9885824398 |
| 13 | 66284043461 |
| 14 | 444431768220 |
| 15 | 2979896612959 |
| 16 | 19980083465882 |
| 17 | 133965632756376 |
| 18 | 898234023419479 |
| 19 | 6022621953315440 |
| 20 | 40381430948778393 |
| 21 | 270755823312682408 |
[1,8,54,361,2420,16227,108802,729512,4891347, 32796280,219897701,1474404984,9885824398, 66284043461,444431768220,2979896612959, 19980083465882,133965632756376,898234023419479, 6022621953315440,40381430948778393, 270755823312682408] |