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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 16 |
| 2 | 172 |
| 3 | 1576 |
| 4 | 13327 |
| 5 | 107704 |
| 6 | 846712 |
| 7 | 6538984 |
| 8 | 49898962 |
| 9 | 377631424 |
| 10 | 2841043912 |
| 11 | 21282493456 |
| 12 | 158924064187 |
| 13 | 1183932211336 |
| 14 | 8804131172992 |
| 15 | 65381568835816 |
| 16 | 485035381715182 |
| 17 | 3595400186709664 |
| 18 | 26635363825706632 |
| 19 | 197229161079953584 |
| 20 | 1459938029383686646 |
[1,16,172,1576,13327,107704,846712,6538984, 49898962,377631424,2841043912,21282493456, 158924064187,1183932211336,8804131172992, 65381568835816,485035381715182,3595400186709664, 26635363825706632,197229161079953584, 1459938029383686646] |