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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 11 |
| 6 | 40 |
| 7 | 99 |
| 8 | 589 |
| 9 | 3194 |
| 10 | 11259 |
| 11 | 92159 |
| 12 | 666160 |
| 13 | 3052323 |
| 14 | 31799041 |
| 15 | 287316122 |
| 16 | 1620265923 |
| 17 | 20497038755 |
| 18 | 222237912664 |
| 19 | 1488257158851 |
| 20 | 22149498351205 |
| 21 | 280180369563194 |
| 22 | 2172534146099019 |
| 23 | 37183508549366519 |
| 24 | 537546603651987424 |
| 25 | 4736552519729393091 |
[1,1,1,2,3,11,40,99,589,3194,11259,92159,666160, 3052323,31799041,287316122,1620265923,20497038755, 222237912664,1488257158851,22149498351205, 280180369563194,2172534146099019, 37183508549366519,537546603651987424, 4736552519729393091] |