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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 57 |
| 5 | 211 |
| 6 | 793 |
| 7 | 3004 |
| 8 | 11441 |
| 9 | 43759 |
| 10 | 167961 |
| 11 | 646647 |
| 12 | 2496145 |
| 13 | 9657701 |
| 14 | 37442161 |
| 15 | 145422676 |
| 16 | 565722721 |
| 17 | 2203961431 |
| 18 | 8597496601 |
| 19 | 33578000611 |
| 20 | 131282408401 |
| 21 | 513791607421 |
| 22 | 2012616400081 |
| 23 | 7890371113951 |
| 24 | 30957699535777 |
| 25 | 121548660036301 |
| 26 | 477551179875953 |
[1,2,5,16,57,211,793,3004,11441,43759,167961, 646647,2496145,9657701,37442161,145422676, 565722721,2203961431,8597496601,33578000611, 131282408401,513791607421,2012616400081, 7890371113951,30957699535777,121548660036301, 477551179875953] |