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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 2 |
| 6 | 5 |
| 7 | 32 |
| 8 | 93 |
| 9 | 261 |
| 10 | 1082 |
| 11 | 3253 |
| 12 | 12307 |
| 13 | 40809 |
| 14 | 153392 |
| 15 | 525417 |
| 16 | 1892876 |
| 17 | 6847161 |
| 18 | 25256461 |
| 19 | 91268129 |
| 20 | 335852960 |
| 21 | 1239350769 |
| 22 | 4606651034 |
| 23 | 17073491494 |
| 24 | 63523866957 |
| 25 | 237953442636 |
| 26 | 892247156886 |
| 27 | 3346127378391 |
| 28 | 12603121634857 |
| 29 | 47642071407103 |
[0,0,0,1,2,5,32,93,261,1082,3253,12307,40809, 153392,525417,1892876,6847161,25256461,91268129, 335852960,1239350769,4606651034,17073491494, 63523866957,237953442636,892247156886, 3346127378391,12603121634857,47642071407103] |