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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 3 | 18 |
| 4 | 30 |
| 5 | 107 |
| 6 | 265 |
| 7 | 553 |
| 8 | 1505 |
| 9 | 3852 |
| 10 | 8922 |
| 11 | 22477 |
| 12 | 56889 |
| 13 | 137617 |
| 14 | 340401 |
| 15 | 851098 |
| 16 | 2091618 |
| 17 | 5160851 |
| 18 | 12817517 |
| 19 | 31655009 |
| 20 | 78159377 |
| 21 | 193558964 |
| 22 | 478614470 |
| 23 | 1182673261 |
| 24 | 2925763109 |
| 25 | 7235864705 |
| 26 | 17887850273 |
| 27 | 44237338898 |
| 28 | 109401520982 |
[1,9,18,30,107,265,553,1505,3852,8922,22477,56889, 137617,340401,851098,2091618,5160851,12817517, 31655009,78159377,193558964,478614470,1182673261, 2925763109,7235864705,17887850273,44237338898, 109401520982] |