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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 30 |
| 6 | 71 |
| 7 | 134 |
| 8 | 296 |
| 9 | 551 |
| 10 | 1188 |
| 11 | 2211 |
| 12 | 4720 |
| 13 | 8815 |
| 14 | 18722 |
| 15 | 35105 |
| 16 | 74307 |
| 17 | 139842 |
| 18 | 295223 |
| 19 | 557366 |
| 20 | 1174031 |
| 21 | 2222606 |
| 22 | 4672473 |
| 23 | 8866776 |
| 24 | 18607461 |
| 25 | 35384676 |
| 26 | 74139407 |
| 27 | 141248270 |
| 28 | 295524297 |
| 29 | 563959752 |
| 30 | 1178389423 |
| 31 | 2252131246 |
| 32 | 4700155088 |
| 33 | 8995122383 |
| 34 | 18751860084 |
[0,0,2,5,15,30,71,134,296,551,1188,2211,4720,8815, 18722,35105,74307,139842,295223,557366,1174031, 2222606,4672473,8866776,18607461,35384676, 74139407,141248270,295524297,563959752,1178389423, 2252131246,4700155088,8995122383,18751860084] |