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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 5 |
| 2 | 9 |
| 3 | 23 |
| 4 | 69 |
| 5 | 210 |
| 6 | 627 |
| 7 | 1846 |
| 8 | 5405 |
| 9 | 15809 |
| 10 | 46254 |
| 11 | 135382 |
| 12 | 396327 |
| 13 | 1160294 |
| 14 | 3396892 |
| 15 | 9944688 |
| 16 | 29113741 |
| 17 | 85232259 |
| 18 | 249522603 |
| 19 | 730492701 |
| 20 | 2138562494 |
| 21 | 6260774221 |
| 22 | 18328804756 |
| 23 | 53658712275 |
| 24 | 157089206159 |
| 25 | 459888386910 |
[4,5,9,23,69,210,627,1846,5405,15809,46254,135382, 396327,1160294,3396892,9944688,29113741,85232259, 249522603,730492701,2138562494,6260774221, 18328804756,53658712275,157089206159,459888386910] |