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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 18 |
| 3 | 77 |
| 4 | 324 |
| 5 | 1375 |
| 6 | 5832 |
| 7 | 24744 |
| 8 | 104976 |
| 9 | 445376 |
| 10 | 1889568 |
| 11 | 8016759 |
| 12 | 34012224 |
| 13 | 144301646 |
| 14 | 612220032 |
| 15 | 2597429618 |
| 16 | 11019960576 |
| 17 | 46753733111 |
| 18 | 198359290368 |
| 19 | 841567195984 |
| 20 | 3570467226624 |
| 21 | 15148209527701 |
[1,5,18,77,324,1375,5832,24744,104976,445376, 1889568,8016759,34012224,144301646,612220032, 2597429618,11019960576,46753733111,198359290368, 841567195984,3570467226624,15148209527701] |