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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 28 |
| 6 | 92 |
| 7 | 251 |
| 8 | 860 |
| 9 | 2513 |
| 10 | 9147 |
| 11 | 28003 |
| 12 | 104286 |
| 13 | 332940 |
| 14 | 1264621 |
| 15 | 4143576 |
| 16 | 16059654 |
| 17 | 53812043 |
| 18 | 210796710 |
| 19 | 719697420 |
| 20 | 2851086259 |
| 21 | 9873316114 |
| 22 | 39477178907 |
| 23 | 138480427194 |
| 24 | 557399401255 |
| 25 | 1976326100848 |
| 26 | 8008908870844 |
| 27 | 28656426926198 |
| 28 | 116748517621235 |
| 29 | 421186490480246 |
| 30 | 1723888841623296 |
[1,1,2,4,12,28,92,251,860,2513,9147,28003,104286, 332940,1264621,4143576,16059654,53812043, 210796710,719697420,2851086259,9873316114, 39477178907,138480427194,557399401255, 1976326100848,8008908870844,28656426926198, 116748517621235,421186490480246,1723888841623296] |