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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 4 |
| 4 | 13 |
| 5 | 22 |
| 6 | 84 |
| 7 | 169 |
| 8 | 585 |
| 9 | 1368 |
| 10 | 4352 |
| 11 | 11018 |
| 12 | 33610 |
| 13 | 89097 |
| 14 | 265059 |
| 15 | 724070 |
| 16 | 2122093 |
| 17 | 5909279 |
| 18 | 17178016 |
| 19 | 48426584 |
| 20 | 140179658 |
| 21 | 398403254 |
| 22 | 1150970558 |
| 23 | 3289206057 |
| 24 | 9495961430 |
| 25 | 27241417922 |
| 26 | 78650410773 |
| 27 | 226250990962 |
| 28 | 653512163209 |
[1,3,4,13,22,84,169,585,1368,4352,11018,33610, 89097,265059,724070,2122093,5909279,17178016, 48426584,140179658,398403254,1150970558, 3289206057,9495961430,27241417922,78650410773, 226250990962,653512163209] |