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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 67 |
| 5 | 343 |
| 6 | 2151 |
| 7 | 9860 |
| 8 | 53739 |
| 9 | 279360 |
| 10 | 1595454 |
| 11 | 8733436 |
| 12 | 53035750 |
| 13 | 280946972 |
| 14 | 1626421033 |
| 15 | 9103196607 |
| 16 | 53266673126 |
| 17 | 300953629850 |
| 18 | 1817236258604 |
| 19 | 10114067087883 |
| 20 | 59666856128423 |
| 21 | 342703064143223 |
| 22 | 2024687556279346 |
| 23 | 11644875879288821 |
| 24 | 70172335165701018 |
[1,1,4,14,67,343,2151,9860,53739,279360,1595454, 8733436,53035750,280946972,1626421033,9103196607, 53266673126,300953629850,1817236258604, 10114067087883,59666856128423,342703064143223, 2024687556279346,11644875879288821, 70172335165701018] |