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| n | a(n) |
|---|---|
| 1 | 360 |
| 2 | 978 |
| 3 | 3888 |
| 4 | 17532 |
| 5 | 80916 |
| 6 | 376314 |
| 7 | 1756446 |
| 8 | 8212662 |
| 9 | 38432652 |
| 10 | 179925948 |
| 11 | 842504430 |
| 12 | 3945403368 |
| 13 | 18476947170 |
| 14 | 86532335682 |
| 15 | 405257580870 |
| 16 | 1897955537136 |
| 17 | 8888775949212 |
| 18 | 41629230515718 |
| 19 | 194964278279712 |
| 20 | 913086294849486 |
[360,978,3888,17532,80916,376314,1756446,8212662, 38432652,179925948,842504430,3945403368, 18476947170,86532335682,405257580870, 1897955537136,8888775949212,41629230515718, 194964278279712,913086294849486] |