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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 26 |
| 6 | 77 |
| 7 | 236 |
| 8 | 741 |
| 9 | 2430 |
| 10 | 8179 |
| 11 | 28208 |
| 12 | 99475 |
| 13 | 356501 |
| 14 | 1296199 |
| 15 | 4783652 |
| 16 | 17871126 |
| 17 | 67465415 |
| 18 | 257298969 |
| 19 | 989810000 |
| 20 | 3838658082 |
| 21 | 15001356476 |
| 22 | 59013879343 |
| 23 | 233616780902 |
| 24 | 930237304959 |
| 25 | 3723778727143 |
| 26 | 14981506373914 |
| 27 | 60554119697080 |
| 28 | 245812410995518 |
| 29 | 1001928721763590 |
| 30 | 4099422669401518 |
[1,1,2,4,10,26,77,236,741,2430,8179,28208,99475, 356501,1296199,4783652,17871126,67465415, 257298969,989810000,3838658082,15001356476, 59013879343,233616780902,930237304959, 3723778727143,14981506373914,60554119697080, 245812410995518,1001928721763590,4099422669401518] |