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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 108 |
| 4 | 6672 |
| 5 | 109200 |
| 6 | 45007920 |
| 7 | 983324160 |
| 8 | 665546434560 |
| 9 | 60174422501760 |
| 10 | 32648180513760000 |
| 11 | 4656975300322329600 |
| 12 | 13859947861644771532800 |
| 13 | 1193599114668580293273600 |
| 14 | 1257285172911535450293811200 |
| 15 | 766119340152013216053484800000 |
[1,1,10,108,6672,109200,45007920,983324160, 665546434560,60174422501760,32648180513760000, 4656975300322329600,13859947861644771532800, 1193599114668580293273600, 1257285172911535450293811200, 766119340152013216053484800000] |