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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 33 |
| 3 | 226 |
| 4 | 1566 |
| 5 | 10902 |
| 6 | 76047 |
| 7 | 530876 |
| 8 | 3706626 |
| 9 | 25876354 |
| 10 | 180589843 |
| 11 | 1259827146 |
| 12 | 8784898992 |
| 13 | 61229779780 |
| 14 | 426567021204 |
| 15 | 2970386408096 |
| 16 | 20674948519258 |
| 17 | 143842673407986 |
| 18 | 1000344408813387 |
| 19 | 6954033779333206 |
| 20 | 48323287425710286 |
| 21 | 335672254266040318 |
[1,5,33,226,1566,10902,76047,530876,3706626, 25876354,180589843,1259827146,8784898992, 61229779780,426567021204,2970386408096, 20674948519258,143842673407986,1000344408813387, 6954033779333206,48323287425710286, 335672254266040318] |