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| n | a(n) |
|---|---|
| 15 | 1 |
| 16 | 7 |
| 17 | 26 |
| 18 | 91 |
| 19 | 291 |
| 20 | 885 |
| 21 | 2588 |
| 22 | 7373 |
| 23 | 20555 |
| 24 | 56413 |
| 25 | 152812 |
| 26 | 409696 |
| 27 | 1089029 |
| 28 | 2874506 |
| 29 | 7542257 |
| 30 | 19690939 |
| 31 | 51188137 |
| 32 | 132579401 |
| 33 | 342294012 |
| 34 | 881292334 |
| 35 | 2263535926 |
| 36 | 5801350565 |
| 37 | 14840644204 |
| 38 | 37901021924 |
| 39 | 96650247055 |
| 40 | 246137463494 |
| 41 | 626087267035 |
| 42 | 1590840361215 |
[1,7,26,91,291,885,2588,7373,20555,56413,152812, 409696,1089029,2874506,7542257,19690939,51188137, 132579401,342294012,881292334,2263535926, 5801350565,14840644204,37901021924,96650247055, 246137463494,626087267035,1590840361215] |