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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 2 |
| 5 | 18 |
| 6 | 42 |
| 7 | 66 |
| 8 | 168 |
| 9 | 300 |
| 10 | 910 |
| 11 | 1882 |
| 12 | 3192 |
| 13 | 5320 |
| 14 | 7166 |
| 15 | 8346 |
| 16 | 9042 |
| 17 | 7760 |
| 18 | 6668 |
| 19 | 4620 |
| 20 | 2822 |
| 21 | 1528 |
| 22 | 942 |
| 23 | 282 |
| 24 | 92 |
| 25 | 32 |
| 26 | 22 |
| 27 | 88 |
| 28 | 256 |
| 29 | 24 |
[0,1,2,2,18,42,66,168,300,910,1882,3192,5320,7166, 8346,9042,7760,6668,4620,2822,1528,942,282,92,32, 22,88,256,24] |