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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 85 |
| 4 | 799 |
| 5 | 5839 |
| 6 | 51395 |
| 7 | 406575 |
| 8 | 3500269 |
| 9 | 28684325 |
| 10 | 245319361 |
| 11 | 2048301005 |
| 12 | 17499467353 |
| 13 | 147731409251 |
| 14 | 1263413909311 |
| 15 | 10741266363733 |
| 16 | 92019265611439 |
| 17 | 786112365529335 |
| 18 | 6747253002120179 |
| 19 | 57843127733658007 |
| 20 | 497375672047480891 |
[1,15,85,799,5839,51395,406575,3500269,28684325, 245319361,2048301005,17499467353,147731409251, 1263413909311,10741266363733,92019265611439, 786112365529335,6747253002120179, 57843127733658007,497375672047480891] |