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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 65 |
| 4 | 994 |
| 5 | 19386 |
| 6 | 456940 |
| 7 | 12594465 |
| 8 | 396969930 |
| 9 | 14078044862 |
| 10 | 554782989908 |
| 11 | 24053551260186 |
| 12 | 1138039204281236 |
| 13 | 58353983394380500 |
| 14 | 3223791843357228120 |
| 15 | 190914111715994215905 |
| 16 | 12065701995815379444954 |
| 17 | 810602692757305194731094 |
| 18 | 57688894099612173692496580 |
[1,1,6,65,994,19386,456940,12594465,396969930, 14078044862,554782989908,24053551260186, 1138039204281236,58353983394380500, 3223791843357228120,190914111715994215905, 12065701995815379444954,810602692757305194731094, 57688894099612173692496580] |