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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 63 |
| 6 | 271 |
| 7 | 1225 |
| 8 | 5726 |
| 9 | 27461 |
| 10 | 134461 |
| 11 | 669795 |
| 12 | 3384945 |
| 13 | 17316771 |
| 14 | 89518347 |
| 15 | 466932059 |
| 16 | 2454546192 |
| 17 | 12990743783 |
| 18 | 69164599115 |
| 19 | 370186756425 |
| 20 | 1990638982239 |
| 21 | 10749412063853 |
| 22 | 58265968105385 |
| 23 | 316903203993921 |
[1,2,5,16,63,271,1225,5726,27461,134461,669795, 3384945,17316771,89518347,466932059,2454546192, 12990743783,69164599115,370186756425, 1990638982239,10749412063853,58265968105385, 316903203993921] |