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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 20 |
| 3 | 78 |
| 4 | 297 |
| 5 | 1130 |
| 6 | 4225 |
| 7 | 15472 |
| 8 | 54143 |
| 9 | 178274 |
| 10 | 508805 |
| 11 | 1062164 |
| 12 | 1195536 |
| 13 | 557174 |
| 14 | 51373 |
| 15 | 103 |
[1,5,20,78,297,1130,4225,15472,54143,178274, 508805,1062164,1195536,557174,51373,103] |