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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 12 |
| 3 | 60 |
| 4 | 1074 |
| 5 | 12400 |
| 6 | 162288 |
| 7 | 2049324 |
| 8 | 26149710 |
| 9 | 332659424 |
| 10 | 4235875140 |
| 11 | 53922195170 |
| 12 | 686478044994 |
| 13 | 8739276731656 |
| 14 | 111257016629792 |
| 15 | 1416375531056864 |
| 16 | 18031410076232628 |
| 17 | 229551897159731062 |
| 18 | 2922349174918753464 |
[0,12,60,1074,12400,162288,2049324,26149710, 332659424,4235875140,53922195170,686478044994, 8739276731656,111257016629792,1416375531056864, 18031410076232628,229551897159731062, 2922349174918753464] |