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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 25 |
| 5 | 86 |
| 6 | 294 |
| 7 | 1024 |
| 8 | 3817 |
| 9 | 14242 |
| 10 | 54008 |
| 11 | 208696 |
| 12 | 811078 |
| 13 | 3195510 |
| 14 | 12739105 |
| 15 | 50994738 |
| 16 | 205890076 |
| 17 | 836663641 |
| 18 | 3415423985 |
| 19 | 14032729088 |
| 20 | 57915331555 |
| 21 | 239929351225 |
| 22 | 998341477817 |
| 23 | 4168025001135 |
| 24 | 17460273027901 |
| 25 | 73393532119090 |
| 26 | 309339627471817 |
| 27 | 1307340906252813 |
| 28 | 5539469603511181 |
[1,1,3,8,25,86,294,1024,3817,14242,54008,208696, 811078,3195510,12739105,50994738,205890076, 836663641,3415423985,14032729088,57915331555, 239929351225,998341477817,4168025001135, 17460273027901,73393532119090,309339627471817, 1307340906252813,5539469603511181] |