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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 15 |
| 4 | 133 |
| 5 | 281 |
| 6 | 414 |
| 7 | 1109 |
| 8 | 1523 |
| 9 | 4155 |
| 10 | 34763 |
| 11 | 38918 |
| 12 | 268271 |
| 13 | 575460 |
| 14 | 20984831 |
| 15 | 42545122 |
| 16 | 276255563 |
| 17 | 318800685 |
| 18 | 2826661043 |
| 19 | 5972122771 |
| 20 | 8798783814 |
| 21 | 23569690399 |
| 22 | 32368474213 |
| 23 | 88306638825 |
| 24 | 738821584813 |
| 25 | 827128223638 |
| 26 | 5701590926641 |
| 27 | 12230310076920 |
[1,2,13,15,133,281,414,1109,1523,4155,34763,38918, 268271,575460,20984831,42545122,276255563, 318800685,2826661043,5972122771,8798783814, 23569690399,32368474213,88306638825,738821584813, 827128223638,5701590926641,12230310076920] |