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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 1 |
| 7 | 15 |
| 8 | 33 |
| 9 | 56 |
| 10 | 495 |
| 11 | 420 |
| 12 | 330 |
| 13 | 3960 |
| 14 | 3432 |
| 15 | 3003 |
| 16 | 2574 |
| 17 | 80080 |
| 18 | 1601145 |
| 19 | 1225224 |
| 20 | 1108536 |
| 21 | 1007760 |
| 22 | 912912 |
| 23 | 19399380 |
| 24 | 17612595 |
| 25 | 82372752 |
| 26 | 149978400 |
| 27 | 212469400 |
| 28 | 196846650 |
| 29 | 5354228880 |
| 30 | 4976687100 |
| 31 | 145568097675 |
| 32 | 273491577450 |
| 33 | 257403837600 |
| 34 | 242695046880 |
[1,1,1,2,4,1,15,33,56,495,420,330,3960,3432,3003, 2574,80080,1601145,1225224,1108536,1007760,912912, 19399380,17612595,82372752,149978400,212469400, 196846650,5354228880,4976687100,145568097675, 273491577450,257403837600,242695046880] |