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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 0 |
| 5 | 3 |
| 6 | 21 |
| 7 | 0 |
| 8 | 4 |
| 9 | 40 |
| 10 | 232 |
| 11 | 0 |
| 12 | 5 |
| 13 | 65 |
| 14 | 505 |
| 15 | 3005 |
| 16 | 0 |
| 17 | 6 |
| 18 | 96 |
| 19 | 936 |
| 20 | 7056 |
| 21 | 45936 |
| 22 | 0 |
| 23 | 7 |
| 24 | 133 |
| 25 | 1561 |
| 26 | 14287 |
| 27 | 112609 |
| 28 | 818503 |
| 29 | 0 |
| 30 | 8 |
| 31 | 176 |
| 32 | 2416 |
| 33 | 26048 |
| 34 | 241984 |
| 35 | 2056832 |
| 36 | 16736896 |
| 37 | 0 |
| 38 | 9 |
| 39 | 225 |
| 40 | 3537 |
| 41 | 43929 |
| 42 | 470961 |
| 43 | 4601529 |
| 44 | 42683841 |
| 45 | 387057609 |
| 46 | 0 |
| 47 | 10 |
| 48 | 280 |
| 49 | 4960 |
| 50 | 69760 |
| 51 | 848800 |
[0,0,2,0,3,21,0,4,40,232,0,5,65,505,3005,0,6,96, 936,7056,45936,0,7,133,1561,14287,112609,818503,0, 8,176,2416,26048,241984,2056832,16736896,0,9,225, 3537,43929,470961,4601529,42683841,387057609,0,10, 280,4960,69760,848800] |