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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 50 |
| 5 | 274 |
| 6 | 394 |
| 7 | 908 |
| 8 | 2964 |
| 9 | 12576 |
| 10 | 65760 |
| 11 | 80160 |
| 12 | 174720 |
| 13 | 552960 |
| 14 | 2298240 |
| 15 | 11836800 |
| 16 | 13564800 |
| 17 | 28857600 |
| 18 | 90028800 |
| 19 | 370483200 |
| 20 | 1893888000 |
| 21 | 2101248000 |
| 22 | 4409856000 |
| 23 | 13644288000 |
| 24 | 55821312000 |
| 25 | 284083200000 |
| 26 | 308966400000 |
[1,3,11,50,274,394,908,2964,12576,65760,80160, 174720,552960,2298240,11836800,13564800,28857600, 90028800,370483200,1893888000,2101248000, 4409856000,13644288000,55821312000,284083200000, 308966400000] |