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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 24 |
| 4 | 50 |
| 5 | 204 |
| 6 | 364 |
| 7 | 1832 |
| 8 | 2916 |
| 9 | 9730 |
| 10 | 14476 |
| 11 | 71856 |
| 12 | 103818 |
| 13 | 282912 |
| 14 | 393840 |
| 15 | 1802704 |
| 16 | 2452114 |
| 17 | 6275898 |
| 18 | 8292056 |
| 19 | 42023440 |
| 20 | 55922412 |
| 21 | 130059138 |
| 22 | 169418920 |
| 23 | 659362200 |
| 24 | 850307750 |
| 25 | 1876260022 |
| 26 | 2376769824 |
| 27 | 11577739208 |
| 28 | 14815959930 |
[1,2,6,24,50,204,364,1832,2916,9730,14476,71856, 103818,282912,393840,1802704,2452114,6275898, 8292056,42023440,55922412,130059138,169418920, 659362200,850307750,1876260022,2376769824, 11577739208,14815959930] |