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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 31 |
| 5 | 141 |
| 6 | 819 |
| 7 | 5562 |
| 8 | 43773 |
| 9 | 389203 |
| 10 | 3858136 |
| 11 | 42152116 |
| 12 | 503098359 |
| 13 | 6511429138 |
| 14 | 90824834615 |
| 15 | 1358130449902 |
| 16 | 21672033893102 |
| 17 | 367570633594883 |
| 18 | 6602838664294634 |
| 19 | 125228962373218571 |
| 20 | 2500582942246200527 |
| 21 | 52437202425839368049 |
| 22 | 1152133477802718430790 |
[1,1,3,8,31,141,819,5562,43773,389203,3858136, 42152116,503098359,6511429138,90824834615, 1358130449902,21672033893102,367570633594883, 6602838664294634,125228962373218571, 2500582942246200527,52437202425839368049, 1152133477802718430790] |