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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 28 |
| 4 | 104 |
| 5 | 384 |
| 6 | 1428 |
| 7 | 5316 |
| 8 | 19820 |
| 9 | 73948 |
| 10 | 276044 |
| 11 | 1030796 |
| 12 | 3850048 |
| 13 | 14382248 |
| 14 | 53732172 |
| 15 | 200759004 |
| 16 | 750134520 |
| 17 | 2802980640 |
| 18 | 10474015164 |
| 19 | 39139487292 |
| 20 | 146259311592 |
| 21 | 546558514368 |
| 22 | 2042458815324 |
| 23 | 7632600834924 |
| 24 | 28522903136796 |
[1,2,8,28,104,384,1428,5316,19820,73948,276044, 1030796,3850048,14382248,53732172,200759004, 750134520,2802980640,10474015164,39139487292, 146259311592,546558514368,2042458815324, 7632600834924,28522903136796] |