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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 12 |
| 4 | 151 |
| 5 | 2545 |
| 6 | 54466 |
| 7 | 1417318 |
| 8 | 43472780 |
| 9 | 1536228588 |
| 10 | 61466251616 |
| 11 | 2746907348768 |
| 12 | 135619260805568 |
| 13 | 7331022129923648 |
| 14 | 430638151053316480 |
| 15 | 27315015477709844352 |
| 16 | 1860627613021322933248 |
| 17 | 135465573609158928964096 |
| 18 | 10498038569346091127451136 |
| 19 | 862792664850194915870874112 |
[0,1,12,151,2545,54466,1417318,43472780, 1536228588,61466251616,2746907348768, 135619260805568,7331022129923648, 430638151053316480,27315015477709844352, 1860627613021322933248,135465573609158928964096, 10498038569346091127451136, 862792664850194915870874112] |