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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 21 |
| 3 | 85 |
| 4 | 320 |
| 5 | 1168 |
| 6 | 4360 |
| 7 | 16428 |
| 8 | 62348 |
| 9 | 238972 |
| 10 | 924028 |
| 11 | 3597324 |
| 12 | 14093900 |
| 13 | 55467612 |
| 14 | 219171356 |
| 15 | 868441132 |
[1,5,21,85,320,1168,4360,16428,62348,238972, 924028,3597324,14093900,55467612,219171356, 868441132] |