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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 43 |
| 4 | 271 |
| 5 | 1746 |
| 6 | 11425 |
| 7 | 75615 |
| 8 | 504799 |
| 9 | 3392953 |
| 10 | 22930282 |
| 11 | 155664356 |
| 12 | 1060710457 |
| 13 | 7250779238 |
| 14 | 49700101101 |
| 15 | 341474150583 |
| 16 | 2351032782783 |
| 17 | 16216401440106 |
| 18 | 112035931072915 |
| 19 | 775163096510445 |
| 20 | 5370301986029066 |
| 21 | 37249469056575504 |
| 22 | 258648802856972348 |
[1,1,7,43,271,1746,11425,75615,504799,3392953, 22930282,155664356,1060710457,7250779238, 49700101101,341474150583,2351032782783, 16216401440106,112035931072915,775163096510445, 5370301986029066,37249469056575504, 258648802856972348] |