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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 65 |
| 2 | 2080 |
| 3 | 43680 |
| 4 | 677040 |
| 5 | 8259888 |
| 6 | 82598880 |
| 7 | 696190560 |
| 8 | 5047381560 |
| 9 | 31966749880 |
| 10 | 179013799328 |
| 11 | 895068996640 |
| 12 | 4027810484880 |
| 13 | 16421073515280 |
| 14 | 60992558771040 |
| 15 | 207374699821536 |
| 16 | 648045936942300 |
| 17 | 1867897112363100 |
| 18 | 4981058966301600 |
| 19 | 12321566916640800 |
[1,65,2080,43680,677040,8259888,82598880, 696190560,5047381560,31966749880,179013799328, 895068996640,4027810484880,16421073515280, 60992558771040,207374699821536,648045936942300, 1867897112363100,4981058966301600, 12321566916640800] |