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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 17 |
| 5 | 89 |
| 6 | 556 |
| 7 | 4011 |
| 8 | 32843 |
| 9 | 301210 |
| 10 | 3059625 |
| 11 | 34104275 |
| 12 | 413919214 |
| 13 | 5434093341 |
| 14 | 76734218273 |
| 15 | 1159776006262 |
| 16 | 18681894258591 |
| 17 | 319512224705645 |
| 18 | 5782488507020050 |
| 19 | 110407313135273127 |
| 20 | 2218005876646727423 |
| 21 | 46767874983437110354 |
| 22 | 1032732727339665789981 |
[1,1,2,4,17,89,556,4011,32843,301210,3059625, 34104275,413919214,5434093341,76734218273, 1159776006262,18681894258591,319512224705645, 5782488507020050,110407313135273127, 2218005876646727423,46767874983437110354, 1032732727339665789981] |