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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 6 |
| 5 | 25 |
| 6 | 100 |
| 7 | 511 |
| 8 | 3626 |
| 9 | 30045 |
| 10 | 262800 |
| 11 | 2470171 |
| 12 | 25889446 |
| 13 | 302003065 |
| 14 | 3821936300 |
| 15 | 51672723831 |
| 16 | 745789322466 |
| 17 | 11505096936085 |
| 18 | 189023074558600 |
| 19 | 3288243760145491 |
| 20 | 60319276499454686 |
| 21 | 1164282909466221105 |
| 22 | 23603464830964817700 |
| 23 | 501435697062735519151 |
[1,6,25,100,511,3626,30045,262800,2470171, 25889446,302003065,3821936300,51672723831, 745789322466,11505096936085,189023074558600, 3288243760145491,60319276499454686, 1164282909466221105,23603464830964817700, 501435697062735519151] |