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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 10 |
| 6 | 21 |
| 7 | 52 |
| 8 | 147 |
| 9 | 564 |
| 10 | 1651 |
| 11 | 4440 |
| 12 | 12499 |
| 13 | 36853 |
| 14 | 116476 |
| 15 | 390774 |
| 16 | 1352215 |
| 17 | 4593736 |
| 18 | 15057127 |
| 19 | 48419013 |
| 20 | 156073723 |
| 21 | 511324062 |
| 22 | 1713185811 |
| 23 | 5878350249 |
| 24 | 20574046540 |
| 25 | 72771206715 |
| 26 | 257475113013 |
| 27 | 905430711156 |
| 28 | 3160767910928 |
| 29 | 10981916671027 |
[1,1,1,1,6,10,21,52,147,564,1651,4440,12499,36853, 116476,390774,1352215,4593736,15057127,48419013, 156073723,511324062,1713185811,5878350249, 20574046540,72771206715,257475113013,905430711156, 3160767910928,10981916671027] |