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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 37 |
| 6 | 114 |
| 7 | 384 |
| 8 | 1405 |
| 9 | 5542 |
| 10 | 23395 |
| 11 | 105140 |
| 12 | 501157 |
| 13 | 2525266 |
| 14 | 13403833 |
| 15 | 74657894 |
| 16 | 434731997 |
| 17 | 2637999706 |
| 18 | 16641634913 |
| 19 | 108969490492 |
| 20 | 739936135562 |
| 21 | 5207151341656 |
| 22 | 37955824652053 |
| 23 | 286365580836781 |
| 24 | 2234228542466676 |
| 25 | 18006401603873750 |
[1,1,2,5,13,37,114,384,1405,5542,23395,105140, 501157,2525266,13403833,74657894,434731997, 2637999706,16641634913,108969490492,739936135562, 5207151341656,37955824652053,286365580836781, 2234228542466676,18006401603873750] |