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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 2 |
| 3 | 10 |
| 4 | 18 |
| 5 | 98 |
| 6 | 210 |
| 7 | 1194 |
| 8 | 2786 |
| 9 | 16258 |
| 10 | 39906 |
| 11 | 236938 |
| 12 | 601458 |
| 13 | 3615330 |
| 14 | 9399858 |
| 15 | 57024426 |
| 16 | 150947010 |
| 17 | 922283522 |
| 18 | 2475603138 |
| 19 | 15212318730 |
| 20 | 41290579410 |
| 21 | 254909413218 |
| 22 | 698230131858 |
| 23 | 4327273358250 |
| 24 | 11943274468770 |
| 25 | 74260741616514 |
| 26 | 206279837823650 |
| 27 | 1286199407132554 |
[1,2,2,10,18,98,210,1194,2786,16258,39906,236938, 601458,3615330,9399858,57024426,150947010, 922283522,2475603138,15212318730,41290579410, 254909413218,698230131858,4327273358250, 11943274468770,74260741616514,206279837823650, 1286199407132554] |