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| n | a(n) |
|---|---|
| 1 | 60 |
| 2 | 720 |
| 3 | 15600 |
| 4 | 117600 |
| 5 | 1771440 |
| 6 | 4826640 |
| 7 | 24137280 |
| 8 | 47045520 |
| 9 | 148035360 |
| 10 | 594822480 |
| 11 | 887502720 |
| 12 | 2565725040 |
| 13 | 4750102560 |
| 14 | 6321361200 |
| 15 | 10779213120 |
| 16 | 22164358320 |
| 17 | 42180530160 |
| 18 | 51520370640 |
| 19 | 90458377680 |
| 20 | 128100278880 |
[60,720,15600,117600,1771440,4826640,24137280, 47045520,148035360,594822480,887502720,2565725040, 4750102560,6321361200,10779213120,22164358320, 42180530160,51520370640,90458377680,128100278880] |