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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 1 |
| 5 | 0 |
| 6 | 2 |
| 7 | 0 |
| 8 | 10 |
| 9 | 20 |
| 10 | 100 |
| 11 | 206 |
| 12 | 528 |
| 13 | 1008 |
| 14 | 2594 |
| 15 | 5618 |
| 16 | 15246 |
| 17 | 37564 |
| 18 | 100604 |
| 19 | 249758 |
| 20 | 651804 |
| 21 | 1633514 |
| 22 | 4233788 |
| 23 | 10771236 |
| 24 | 28036370 |
| 25 | 72289144 |
| 26 | 188906208 |
| 27 | 490896946 |
| 28 | 1286263486 |
| 29 | 3361239986 |
| 30 | 8831282324 |
| 31 | 23185222496 |
[1,1,0,2,0,10,20,100,206,528,1008,2594,5618,15246, 37564,100604,249758,651804,1633514,4233788, 10771236,28036370,72289144,188906208,490896946, 1286263486,3361239986,8831282324,23185222496] |