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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 1 |
| 6 | 1 |
| 7 | 6 |
| 8 | 6 |
| 9 | 1 |
| 10 | 1 |
| 11 | 20 |
| 12 | 90 |
| 13 | 20 |
| 14 | 1 |
| 15 | 1 |
| 16 | 70 |
| 17 | 1860 |
| 18 | 1860 |
| 19 | 70 |
| 20 | 1 |
| 21 | 1 |
| 22 | 252 |
| 23 | 44730 |
| 24 | 297200 |
| 25 | 44730 |
| 26 | 252 |
| 27 | 1 |
| 28 | 1 |
| 29 | 924 |
| 30 | 1172556 |
| 31 | 60871300 |
| 32 | 60871300 |
| 33 | 1172556 |
| 34 | 924 |
| 35 | 1 |
| 36 | 1 |
| 37 | 3432 |
| 38 | 32496156 |
| 39 | 14367744720 |
| 40 | 116963796250 |
| 41 | 14367744720 |
| 42 | 32496156 |
| 43 | 3432 |
| 44 | 1 |
| 45 | 1 |
| 46 | 12870 |
| 47 | 936369720 |
| 48 | 3718394156400 |
| 49 | 273957842462220 |
| 50 | 273957842462220 |
| 51 | 3718394156400 |
| 52 | 936369720 |
| 53 | 12870 |
| 54 | 1 |
[1,1,1,1,2,1,1,6,6,1,1,20,90,20,1,1,70,1860,1860, 70,1,1,252,44730,297200,44730,252,1,1,924,1172556, 60871300,60871300,1172556,924,1,1,3432,32496156, 14367744720,116963796250,14367744720,32496156, 3432,1,1,12870,936369720,3718394156400, 273957842462220,273957842462220,3718394156400, 936369720,12870,1] |