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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 25 |
| 6 | 72 |
| 7 | 231 |
| 8 | 696 |
| 9 | 2268 |
| 10 | 7030 |
| 11 | 23155 |
| 12 | 73188 |
| 13 | 242957 |
| 14 | 778946 |
| 15 | 2601345 |
| 16 | 8430992 |
| 17 | 28289598 |
| 18 | 92470194 |
| 19 | 311472985 |
| 20 | 1025114180 |
| 21 | 3463982109 |
| 22 | 11465054942 |
| 23 | 38846071490 |
| 24 | 129180293184 |
| 25 | 438697998100 |
| 26 | 1464716085664 |
| 27 | 4984101484479 |
| 28 | 16698145444260 |
| 29 | 56918978668875 |
[1,3,8,25,72,231,696,2268,7030,23155,73188,242957, 778946,2601345,8430992,28289598,92470194, 311472985,1025114180,3463982109,11465054942, 38846071490,129180293184,438697998100, 1464716085664,4984101484479,16698145444260, 56918978668875] |