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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 112 |
| 4 | 1104 |
| 5 | 11778 |
| 6 | 132374 |
| 7 | 1543740 |
| 8 | 18505996 |
| 9 | 226632616 |
| 10 | 2823110349 |
| 11 | 35659080952 |
| 12 | 455652487060 |
| 13 | 5879489288828 |
| 14 | 76502741016012 |
| 15 | 1002670573618324 |
| 16 | 13224761472453756 |
| 17 | 175404372357915096 |
| 18 | 2338003752387818372 |
| 19 | 31302169754776944512 |
| 20 | 420760252068869028028 |
[1,2,13,112,1104,11778,132374,1543740,18505996, 226632616,2823110349,35659080952,455652487060, 5879489288828,76502741016012,1002670573618324, 13224761472453756,175404372357915096, 2338003752387818372,31302169754776944512, 420760252068869028028] |