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| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 4 |
| 7 | 4 |
| 8 | 16 |
| 9 | 32 |
| 10 | 81 |
| 11 | 214 |
| 12 | 506 |
| 13 | 1376 |
| 14 | 3393 |
| 15 | 8274 |
| 16 | 22246 |
| 17 | 55106 |
| 18 | 142366 |
| 19 | 370288 |
| 20 | 946740 |
| 21 | 2466300 |
| 22 | 6422117 |
| 23 | 16733982 |
| 24 | 43912796 |
| 25 | 115412210 |
| 26 | 304122477 |
| 27 | 804376850 |
| 28 | 2131389414 |
| 29 | 5661111084 |
| 30 | 15072342561 |
| 31 | 40200636282 |
[0,0,2,4,4,16,32,81,214,506,1376,3393,8274,22246, 55106,142366,370288,946740,2466300,6422117, 16733982,43912796,115412210,304122477,804376850, 2131389414,5661111084,15072342561,40200636282] |