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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 4098 |
| 3 | 531444 |
| 4 | 16785412 |
| 5 | 244140630 |
| 6 | 2177857512 |
| 7 | 13841287208 |
| 8 | 68753047560 |
| 9 | 282431130813 |
| 10 | 1000488301740 |
| 11 | 3138428376732 |
| 12 | 8920506494928 |
| 13 | 23298085122494 |
| 14 | 56721594978384 |
| 15 | 129747072969720 |
| 16 | 281612482805776 |
| 17 | 582622237229778 |
| 18 | 1157402774071674 |
[0,1,4098,531444,16785412,244140630,2177857512, 13841287208,68753047560,282431130813, 1000488301740,3138428376732,8920506494928, 23298085122494,56721594978384,129747072969720, 281612482805776,582622237229778,1157402774071674] |