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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 18 |
| 5 | 61 |
| 6 | 225 |
| 7 | 825 |
| 8 | 3205 |
| 9 | 12791 |
| 10 | 52429 |
| 11 | 217143 |
| 12 | 911057 |
| 13 | 3867757 |
| 14 | 16646382 |
| 15 | 72368671 |
| 16 | 317076266 |
| 17 | 1398003840 |
| 18 | 6204279946 |
| 19 | 27714426625 |
| 20 | 124522666545 |
| 21 | 562150971473 |
| 22 | 2548318697521 |
| 23 | 11598080400448 |
| 24 | 52994780032247 |
| 25 | 243032840624120 |
| 26 | 1118117316012481 |
| 27 | 5158855695201946 |
| 28 | 23867302101397595 |
[1,1,2,5,18,61,225,825,3205,12791,52429,217143, 911057,3867757,16646382,72368671,317076266, 1398003840,6204279946,27714426625,124522666545, 562150971473,2548318697521,11598080400448, 52994780032247,243032840624120,1118117316012481, 5158855695201946,23867302101397595] |