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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 13 |
| 2 | 42 |
| 3 | 135 |
| 4 | 433 |
| 5 | 1388 |
| 6 | 4449 |
| 7 | 14260 |
| 8 | 45706 |
| 9 | 146496 |
| 10 | 469546 |
| 11 | 1504979 |
| 12 | 4823727 |
| 13 | 15460908 |
| 14 | 49554976 |
| 15 | 158832563 |
| 16 | 509086778 |
| 17 | 1631714194 |
| 18 | 5229935889 |
| 19 | 16762880107 |
| 20 | 53728029453 |
| 21 | 172207945799 |
| 22 | 551957272549 |
[4,13,42,135,433,1388,4449,14260,45706,146496, 469546,1504979,4823727,15460908,49554976, 158832563,509086778,1631714194,5229935889, 16762880107,53728029453,172207945799,551957272549] |