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| n | a(n) |
|---|---|
| 1 | 5 |
| 2 | 2 |
| 3 | 20 |
| 4 | 104 |
| 5 | 560 |
| 6 | 3008 |
| 7 | 16160 |
| 8 | 86816 |
| 9 | 466400 |
| 10 | 2505632 |
| 11 | 13460960 |
| 12 | 72316064 |
| 13 | 388502240 |
| 14 | 2087143328 |
| 15 | 11212721120 |
| 16 | 60237892256 |
| 17 | 323614903520 |
| 18 | 1738550302112 |
| 19 | 9339981317600 |
| 20 | 50177007192224 |
| 21 | 269564998596320 |
| 22 | 1448179007366048 |
| 23 | 7780025034022880 |
| 24 | 41796483184846496 |
[5,2,20,104,560,3008,16160,86816,466400,2505632, 13460960,72316064,388502240,2087143328, 11212721120,60237892256,323614903520, 1738550302112,9339981317600,50177007192224, 269564998596320,1448179007366048,7780025034022880, 41796483184846496] |