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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 24 |
| 5 | 86 |
| 6 | 330 |
| 7 | 1311 |
| 8 | 5326 |
| 9 | 22070 |
| 10 | 92940 |
| 11 | 396466 |
| 12 | 1709610 |
| 13 | 7440200 |
| 14 | 32636590 |
| 15 | 144146831 |
| 16 | 640500188 |
| 17 | 2861175670 |
| 18 | 12841853052 |
| 19 | 57883546774 |
| 20 | 261905659756 |
| 21 | 1189161029092 |
| 22 | 5416356944248 |
| 23 | 24741552146026 |
| 24 | 113317361529586 |
| 25 | 520265301736892 |
| 26 | 2394041095608960 |
| 27 | 11039387236631796 |
[1,1,2,7,24,86,330,1311,5326,22070,92940,396466, 1709610,7440200,32636590,144146831,640500188, 2861175670,12841853052,57883546774,261905659756, 1189161029092,5416356944248,24741552146026, 113317361529586,520265301736892,2394041095608960, 11039387236631796] |