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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 52 |
| 5 | 405 |
| 6 | 3786 |
| 7 | 42301 |
| 8 | 542984 |
| 9 | 7924041 |
| 10 | 129110230 |
| 11 | 2327399481 |
| 12 | 45940938924 |
| 13 | 986045445853 |
| 14 | 22856850513602 |
| 15 | 569163515043285 |
| 16 | 15150885843083536 |
| 17 | 429364157810169105 |
| 18 | 12905794670246364078 |
| 19 | 410108007771441394129 |
| 20 | 13736898888997174964660 |
| 21 | 483740530150449507164901 |
| 22 | 17866185834825657429606682 |
[1,1,2,9,52,405,3786,42301,542984,7924041, 129110230,2327399481,45940938924,986045445853, 22856850513602,569163515043285,15150885843083536, 429364157810169105,12905794670246364078, 410108007771441394129,13736898888997174964660, 483740530150449507164901, 17866185834825657429606682] |