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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 56 |
| 4 | 258 |
| 5 | 1089 |
| 6 | 4394 |
| 7 | 17290 |
| 8 | 67048 |
| 9 | 257754 |
| 10 | 985796 |
| 11 | 3759074 |
| 12 | 14311750 |
| 13 | 54452385 |
| 14 | 207163530 |
| 15 | 788414010 |
| 16 | 3002300400 |
| 17 | 11441617950 |
| 18 | 43641721260 |
| 19 | 166619689080 |
| 20 | 636761192964 |
| 21 | 2435899184922 |
| 22 | 9327702931140 |
| 23 | 35753497006596 |
| 24 | 137177675480048 |
| 25 | 526817306712340 |
[0,1,10,56,258,1089,4394,17290,67048,257754, 985796,3759074,14311750,54452385,207163530, 788414010,3002300400,11441617950,43641721260, 166619689080,636761192964,2435899184922, 9327702931140,35753497006596,137177675480048, 526817306712340] |