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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 36 |
| 2 | 820 |
| 3 | 15120 |
| 4 | 246736 |
| 5 | 3721536 |
| 6 | 53174080 |
| 7 | 730794240 |
| 8 | 9758653696 |
| 9 | 127501710336 |
| 10 | 1638112752640 |
| 11 | 20771546664960 |
| 12 | 260668843872256 |
| 13 | 3244288806567936 |
| 14 | 40111449573376000 |
| 15 | 493276560759521280 |
| 16 | 6039827824481468416 |
| 17 | 73691981266726158336 |
| 18 | 896516001844367196160 |
[1,36,820,15120,246736,3721536,53174080,730794240, 9758653696,127501710336,1638112752640, 20771546664960,260668843872256,3244288806567936, 40111449573376000,493276560759521280, 6039827824481468416,73691981266726158336, 896516001844367196160] |