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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 7 |
| 3 | 16 |
| 4 | 40 |
| 5 | 116 |
| 6 | 395 |
| 7 | 1551 |
| 8 | 6847 |
| 9 | 33290 |
| 10 | 175708 |
| 11 | 996696 |
| 12 | 6031281 |
| 13 | 38710303 |
| 14 | 262288647 |
| 15 | 1868825536 |
| 16 | 13955504572 |
| 17 | 108907053412 |
| 18 | 885935408411 |
| 19 | 7495705968467 |
| 20 | 65829634763895 |
| 21 | 599033379716074 |
| 22 | 5638952863115576 |
| 23 | 54830878201599424 |
| 24 | 549981672834888561 |
[1,3,7,16,40,116,395,1551,6847,33290,175708, 996696,6031281,38710303,262288647,1868825536, 13955504572,108907053412,885935408411, 7495705968467,65829634763895,599033379716074, 5638952863115576,54830878201599424, 549981672834888561] |