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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 16 |
| 4 | 45 |
| 5 | 121 |
| 6 | 320 |
| 7 | 841 |
| 8 | 2205 |
| 9 | 5776 |
| 10 | 15125 |
| 11 | 39601 |
| 12 | 103680 |
| 13 | 271441 |
| 14 | 710645 |
| 15 | 1860496 |
| 16 | 4870845 |
| 17 | 12752041 |
| 18 | 33385280 |
| 19 | 87403801 |
| 20 | 228826125 |
| 21 | 599074576 |
| 22 | 1568397605 |
| 23 | 4106118241 |
| 24 | 10749957120 |
| 25 | 28143753121 |
| 26 | 73681302245 |
| 27 | 192900153616 |
| 28 | 505019158605 |
| 29 | 1322157322201 |
[0,1,5,16,45,121,320,841,2205,5776,15125,39601, 103680,271441,710645,1860496,4870845,12752041, 33385280,87403801,228826125,599074576,1568397605, 4106118241,10749957120,28143753121,73681302245, 192900153616,505019158605,1322157322201] |