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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 18 |
| 2 | 229 |
| 3 | 2538 |
| 4 | 26197 |
| 5 | 259290 |
| 6 | 2498293 |
| 7 | 23637546 |
| 8 | 220808533 |
| 9 | 2043771642 |
| 10 | 18789409717 |
| 11 | 171872944074 |
| 12 | 1566234297109 |
| 13 | 14231753285274 |
| 14 | 129035291862901 |
| 15 | 1167964212866922 |
| 16 | 10558204018573525 |
| 17 | 95349518886691386 |
| 18 | 860425449017192245 |
| 19 | 7759787494414042890 |
| 20 | 69949796622542623381 |
[1,18,229,2538,26197,259290,2498293,23637546, 220808533,2043771642,18789409717,171872944074, 1566234297109,14231753285274,129035291862901, 1167964212866922,10558204018573525, 95349518886691386,860425449017192245, 7759787494414042890,69949796622542623381] |