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| n | a(n) |
|---|---|
| 2 | 2 |
| 3 | 8 |
| 4 | 34 |
| 5 | 136 |
| 6 | 538 |
| 7 | 2080 |
| 8 | 7970 |
| 9 | 30224 |
| 10 | 113874 |
| 11 | 426520 |
| 12 | 1590338 |
| 13 | 5906640 |
| 14 | 21866794 |
| 15 | 80725280 |
| 16 | 297292610 |
| 17 | 1092539736 |
| 18 | 4007553922 |
| 19 | 14675748416 |
| 20 | 53663197698 |
| 21 | 195962433328 |
| 22 | 714734393378 |
| 23 | 2603994002280 |
| 24 | 9477643739746 |
| 25 | 34463730424720 |
[2,8,34,136,538,2080,7970,30224,113874,426520, 1590338,5906640,21866794,80725280,297292610, 1092539736,4007553922,14675748416,53663197698, 195962433328,714734393378,2603994002280, 9477643739746,34463730424720] |