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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 14 |
| 6 | 40 |
| 7 | 118 |
| 8 | 349 |
| 9 | 1042 |
| 10 | 3112 |
| 11 | 9322 |
| 12 | 27926 |
| 13 | 83738 |
| 14 | 251096 |
| 15 | 753170 |
| 16 | 2259161 |
| 17 | 6777134 |
| 18 | 20330360 |
| 19 | 60990038 |
| 20 | 182967002 |
| 21 | 548897894 |
| 22 | 1646684360 |
| 23 | 4940043758 |
| 24 | 14820103348 |
| 25 | 44460282118 |
| 26 | 133380762616 |
| 27 | 400142204110 |
| 28 | 1200426361234 |
| 29 | 3601278832606 |
| 30 | 10803835744648 |
[1,1,2,5,14,40,118,349,1042,3112,9322,27926,83738, 251096,753170,2259161,6777134,20330360,60990038, 182967002,548897894,1646684360,4940043758, 14820103348,44460282118,133380762616,400142204110, 1200426361234,3601278832606,10803835744648] |