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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 32 |
| 4 | 140 |
| 5 | 624 |
| 6 | 2835 |
| 7 | 13083 |
| 8 | 60972 |
| 9 | 286915 |
| 10 | 1358879 |
| 11 | 6471544 |
| 12 | 30958497 |
| 13 | 148639296 |
| 14 | 715975304 |
| 15 | 3458054422 |
| 16 | 16742032860 |
| 17 | 81223525103 |
| 18 | 394774557700 |
| 19 | 1921859283853 |
| 20 | 9369609275641 |
| 21 | 45739130217128 |
| 22 | 223544562299062 |
| 23 | 1093714600090306 |
| 24 | 5356310718357100 |
| 25 | 26255094806635557 |
| 26 | 128799993599104739 |
[1,2,8,32,140,624,2835,13083,60972,286915,1358879, 6471544,30958497,148639296,715975304,3458054422, 16742032860,81223525103,394774557700, 1921859283853,9369609275641,45739130217128, 223544562299062,1093714600090306,5356310718357100, 26255094806635557,128799993599104739] |