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| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 6 |
| 7 | 6 |
| 8 | 16 |
| 9 | 34 |
| 10 | 92 |
| 11 | 256 |
| 12 | 576 |
| 13 | 1374 |
| 14 | 3594 |
| 15 | 9776 |
| 16 | 24120 |
| 17 | 60318 |
| 18 | 158240 |
| 19 | 417258 |
| 20 | 1073864 |
| 21 | 2808084 |
| 22 | 7437688 |
| 23 | 19653510 |
| 24 | 52051176 |
| 25 | 138619116 |
| 26 | 369852718 |
| 27 | 989005920 |
| 28 | 2652718066 |
| 29 | 7128563698 |
| 30 | 19191807302 |
[0,0,2,6,6,16,34,92,256,576,1374,3594,9776,24120, 60318,158240,417258,1073864,2808084,7437688, 19653510,52051176,138619116,369852718,989005920, 2652718066,7128563698,19191807302] |