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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 12 |
| 5 | 60 |
| 6 | 180 |
| 7 | 1152 |
| 8 | 2520 |
| 9 | 7560 |
| 10 | 37332 |
| 11 | 415800 |
| 12 | 1247400 |
| 13 | 16118932 |
| 14 | 112918900 |
| 15 | 564876900 |
| 16 | 1109481408 |
| 17 | 17645365584 |
| 18 | 57890359152 |
| 19 | 1099944846000 |
| 20 | 5468570553600 |
| 21 | 37559092302400 |
| 22 | 421791599312500 |
| 23 | 9256378099515120 |
| 24 | 29207007622737652 |
| 25 | 146100174169950000 |
| 26 | 1880759745476519040 |
| 27 | 5589847741506645552 |
| 28 | 39852571442073216768 |
[1,2,6,12,60,180,1152,2520,7560,37332,415800, 1247400,16118932,112918900,564876900,1109481408, 17645365584,57890359152,1099944846000, 5468570553600,37559092302400,421791599312500, 9256378099515120,29207007622737652, 146100174169950000,1880759745476519040, 5589847741506645552,39852571442073216768] |