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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 44 |
| 4 | 577 |
| 5 | 10104 |
| 6 | 222133 |
| 7 | 5886880 |
| 8 | 182775969 |
| 9 | 6509571200 |
| 10 | 261665344261 |
| 11 | 11720054882304 |
| 12 | 578878362625825 |
| 13 | 31259890045425664 |
| 14 | 1832295378792935925 |
| 15 | 115862322601669627904 |
| 16 | 7861907382202262095297 |
| 17 | 569837358810005613281280 |
| 18 | 43939338917141224534941829 |
[1,1,5,44,577,10104,222133,5886880,182775969, 6509571200,261665344261,11720054882304, 578878362625825,31259890045425664, 1832295378792935925,115862322601669627904, 7861907382202262095297,569837358810005613281280, 43939338917141224534941829] |