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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 26 |
| 5 | 98 |
| 6 | 387 |
| 7 | 1590 |
| 8 | 6699 |
| 9 | 28754 |
| 10 | 125359 |
| 11 | 553696 |
| 12 | 2472267 |
| 13 | 11140492 |
| 14 | 50599174 |
| 15 | 231401382 |
| 16 | 1064646228 |
| 17 | 4924458114 |
| 18 | 22886125061 |
| 19 | 106815213813 |
| 20 | 500447918795 |
| 21 | 2352844049280 |
| 22 | 11096870017710 |
| 23 | 52488362170335 |
| 24 | 248930058920517 |
| 25 | 1183456657164537 |
| 26 | 5639068382464958 |
[1,1,2,7,26,98,387,1590,6699,28754,125359,553696, 2472267,11140492,50599174,231401382,1064646228, 4924458114,22886125061,106815213813,500447918795, 2352844049280,11096870017710,52488362170335, 248930058920517,1183456657164537,5639068382464958] |