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| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 16 |
| 2 | 60 |
| 3 | 384 |
| 4 | 1680 |
| 5 | 12288 |
| 6 | 60480 |
| 7 | 491520 |
| 8 | 2661120 |
| 9 | 23592960 |
| 10 | 138378240 |
| 11 | 1321205760 |
| 12 | 8302694400 |
| 13 | 84557168640 |
| 14 | 564583219200 |
| 15 | 6088116142080 |
| 16 | 42908324659200 |
| 17 | 487049291366400 |
| 18 | 3604299271372800 |
| 19 | 42860337640243200 |
[3,16,60,384,1680,12288,60480,491520,2661120, 23592960,138378240,1321205760,8302694400, 84557168640,564583219200,6088116142080, 42908324659200,487049291366400,3604299271372800, 42860337640243200] |