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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 36 |
| 4 | 144 |
| 5 | 1440 |
| 6 | 17280 |
| 7 | 241920 |
| 8 | 29030400 |
| 9 | 1567641600 |
| 10 | 156764160000 |
| 11 | 217275125760000 |
| 12 | 1738201006080000 |
| 13 | 45193226158080000 |
| 14 | 3796230997278720000 |
| 15 | 113886929918361600000 |
| 16 | 1822190878693785600000 |
| 17 | 22489479824838701875200000 |
| 18 | 28336744579296764362752000000 |
| 19 | 1076796294013277045784576000000 |
| 20 | 1679802218660712191423938560000000 |
[1,2,36,144,1440,17280,241920,29030400,1567641600, 156764160000,217275125760000,1738201006080000, 45193226158080000,3796230997278720000, 113886929918361600000,1822190878693785600000, 22489479824838701875200000, 28336744579296764362752000000, 1076796294013277045784576000000, 1679802218660712191423938560000000] |