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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 56 |
| 3 | 333 |
| 4 | 2232 |
| 5 | 30718 |
| 6 | 314166 |
| 7 | 2561017 |
| 8 | 24729380 |
| 9 | 248623843 |
| 10 | 2294091610 |
| 11 | 21321186497 |
| 12 | 204951390856 |
| 13 | 1942216548168 |
| 14 | 18230545326138 |
| 15 | 172631845704811 |
| 16 | 1636624660988864 |
| 17 | 15453906528343116 |
| 18 | 146032030188390140 |
[1,56,333,2232,30718,314166,2561017,24729380, 248623843,2294091610,21321186497,204951390856, 1942216548168,18230545326138,172631845704811, 1636624660988864,15453906528343116, 146032030188390140] |