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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 56 |
| 3 | 392 |
| 4 | 2737 |
| 5 | 19103 |
| 6 | 133336 |
| 7 | 930664 |
| 8 | 6495881 |
| 9 | 45340183 |
| 10 | 316467032 |
| 11 | 2208887912 |
| 12 | 15417674881 |
| 13 | 107612838767 |
| 14 | 751119942328 |
| 15 | 5242693847944 |
| 16 | 36593142099353 |
| 17 | 255414122498983 |
| 18 | 1782748630735352 |
| 19 | 12443292678154184 |
| 20 | 86852139446231761 |
| 21 | 606213670408228799 |
| 22 | 4231271866564953112 |
[1,8,56,392,2737,19103,133336,930664,6495881, 45340183,316467032,2208887912,15417674881, 107612838767,751119942328,5242693847944, 36593142099353,255414122498983,1782748630735352, 12443292678154184,86852139446231761, 606213670408228799,4231271866564953112] |