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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 140 |
| 7 | 481 |
| 8 | 1740 |
| 9 | 6517 |
| 10 | 25071 |
| 11 | 98909 |
| 12 | 398029 |
| 13 | 1630133 |
| 14 | 6776780 |
| 15 | 28545990 |
| 16 | 121634875 |
| 17 | 523592344 |
| 18 | 2274403486 |
| 19 | 9959936977 |
| 20 | 43935043231 |
| 21 | 195083730751 |
| 22 | 871408143675 |
| 23 | 3913633986985 |
| 24 | 17664173896079 |
| 25 | 80090608816509 |
| 26 | 364658344537497 |
| 27 | 1666732699542652 |
| 28 | 7645308725638059 |
[1,1,2,5,14,42,140,481,1740,6517,25071,98909, 398029,1630133,6776780,28545990,121634875, 523592344,2274403486,9959936977,43935043231, 195083730751,871408143675,3913633986985, 17664173896079,80090608816509,364658344537497, 1666732699542652,7645308725638059] |