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| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 4 |
| 6 | 8 |
| 7 | 4 |
| 8 | 20 |
| 9 | 68 |
| 10 | 108 |
| 11 | 258 |
| 12 | 704 |
| 13 | 1586 |
| 14 | 3600 |
| 15 | 9474 |
| 16 | 23534 |
| 17 | 57098 |
| 18 | 146818 |
| 19 | 381946 |
| 20 | 979169 |
| 21 | 2546468 |
| 22 | 6725314 |
| 23 | 17734622 |
| 24 | 46896938 |
| 25 | 124860502 |
| 26 | 333177050 |
| 27 | 889946916 |
| 28 | 2383867805 |
| 29 | 6398917298 |
| 30 | 17196251103 |
| 31 | 46285522374 |
[0,0,4,8,4,20,68,108,258,704,1586,3600,9474,23534, 57098,146818,381946,979169,2546468,6725314, 17734622,46896938,124860502,333177050,889946916, 2383867805,6398917298,17196251103,46285522374] |