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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 143 |
| 4 | 1852 |
| 5 | 27563 |
| 6 | 473725 |
| 7 | 9290396 |
| 8 | 203745235 |
| 9 | 4912490375 |
| 10 | 128777672338 |
| 11 | 3643086083981 |
| 12 | 110557605978901 |
| 13 | 3579776914324250 |
| 14 | 123074955978249433 |
| 15 | 4474133111905169219 |
| 16 | 171363047274358839412 |
| 17 | 6893620459732188296591 |
| 18 | 290475101469031118494993 |
[1,2,13,143,1852,27563,473725,9290396,203745235, 4912490375,128777672338,3643086083981, 110557605978901,3579776914324250, 123074955978249433,4474133111905169219, 171363047274358839412,6893620459732188296591, 290475101469031118494993] |