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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 11 |
| 3 | 35 |
| 4 | 98 |
| 5 | 260 |
| 6 | 643 |
| 7 | 1563 |
| 8 | 3631 |
| 9 | 8407 |
| 10 | 18833 |
| 11 | 42313 |
| 12 | 92621 |
| 13 | 203973 |
| 14 | 439525 |
| 15 | 954373 |
| 16 | 2033480 |
| 17 | 4369630 |
| 18 | 9232317 |
| 19 | 19680561 |
| 20 | 41311764 |
| 21 | 87507822 |
| 22 | 182738699 |
| 23 | 385095795 |
| 24 | 800788788 |
| 25 | 1680371358 |
| 26 | 3482028637 |
| 27 | 7280492521 |
| 28 | 15041978366 |
[3,11,35,98,260,643,1563,3631,8407,18833,42313, 92621,203973,439525,954373,2033480,4369630, 9232317,19680561,41311764,87507822,182738699, 385095795,800788788,1680371358,3482028637, 7280492521,15041978366] |