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| n | a(n) |
|---|---|
| 1 | 12 |
| 2 | 144 |
| 3 | 612 |
| 4 | 2100 |
| 5 | 8778 |
| 6 | 34668 |
| 7 | 147084 |
| 8 | 617732 |
| 9 | 2671488 |
| 10 | 11581700 |
| 11 | 50920910 |
| 12 | 224964992 |
| 13 | 1001727900 |
| 14 | 4480199928 |
| 15 | 20136395180 |
| 16 | 90815818836 |
| 17 | 410932519010 |
| 18 | 1864187195364 |
| 19 | 8476190423340 |
| 20 | 38611887901692 |
| 21 | 176175077736008 |
[12,144,612,2100,8778,34668,147084,617732,2671488, 11581700,50920910,224964992,1001727900,4480199928, 20136395180,90815818836,410932519010, 1864187195364,8476190423340,38611887901692, 176175077736008] |