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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 2 |
| 7 | 8 |
| 8 | 26 |
| 9 | 74 |
| 10 | 194 |
| 11 | 482 |
| 12 | 1152 |
| 13 | 2674 |
| 14 | 6068 |
| 15 | 13524 |
| 16 | 29704 |
| 17 | 64460 |
| 18 | 138482 |
| 19 | 294988 |
| 20 | 623834 |
| 21 | 1311086 |
| 22 | 2740666 |
| 23 | 5702270 |
| 24 | 11815752 |
| 25 | 24395678 |
| 26 | 50209572 |
| 27 | 103048168 |
| 28 | 210965064 |
| 29 | 430938832 |
| 30 | 878534170 |
[0,0,0,0,0,2,8,26,74,194,482,1152,2674,6068,13524, 29704,64460,138482,294988,623834,1311086,2740666, 5702270,11815752,24395678,50209572,103048168, 210965064,430938832,878534170] |