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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 26 |
| 6 | 75 |
| 7 | 231 |
| 8 | 714 |
| 9 | 2253 |
| 10 | 7439 |
| 11 | 24739 |
| 12 | 83518 |
| 13 | 290505 |
| 14 | 1020477 |
| 15 | 3617151 |
| 16 | 12988441 |
| 17 | 47028018 |
| 18 | 171707245 |
| 19 | 633525246 |
| 20 | 2353982342 |
| 21 | 8798512258 |
| 22 | 33091091756 |
| 23 | 125118844853 |
| 24 | 475659961733 |
| 25 | 1818108173316 |
| 26 | 6980593935149 |
| 27 | 26910085515567 |
| 28 | 104137310867262 |
| 29 | 404464619751576 |
| 30 | 1576642426385280 |
[1,1,2,4,11,26,75,231,714,2253,7439,24739,83518, 290505,1020477,3617151,12988441,47028018, 171707245,633525246,2353982342,8798512258, 33091091756,125118844853,475659961733, 1818108173316,6980593935149,26910085515567, 104137310867262,404464619751576,1576642426385280] |