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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 40 |
| 5 | 163 |
| 6 | 675 |
| 7 | 2886 |
| 8 | 12689 |
| 9 | 56478 |
| 10 | 255603 |
| 11 | 1168905 |
| 12 | 5394434 |
| 13 | 25095146 |
| 14 | 117492138 |
| 15 | 553152779 |
| 16 | 2616933716 |
| 17 | 12431990751 |
| 18 | 59275716489 |
| 19 | 283546088317 |
| 20 | 1360204934717 |
| 21 | 6541812163277 |
| 22 | 31534431432856 |
| 23 | 152322880776339 |
| 24 | 737149995058359 |
| 25 | 3573391008758199 |
| 26 | 17349000852646641 |
| 27 | 84349149920751191 |
[1,1,3,11,40,163,675,2886,12689,56478,255603, 1168905,5394434,25095146,117492138,553152779, 2616933716,12431990751,59275716489,283546088317, 1360204934717,6541812163277,31534431432856, 152322880776339,737149995058359,3573391008758199, 17349000852646641,84349149920751191] |