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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 8 |
| 6 | 38 |
| 7 | 206 |
| 8 | 1200 |
| 9 | 6824 |
| 10 | 50912 |
| 11 | 446752 |
| 12 | 3828592 |
| 13 | 38953680 |
| 14 | 411358960 |
| 15 | 4740541440 |
| 16 | 57933236928 |
| 17 | 759535226432 |
| 18 | 10488778719488 |
| 19 | 156933187370432 |
| 20 | 2425018017191040 |
| 21 | 40031753222399360 |
| 22 | 689218695990369536 |
| 23 | 12461424512466701312 |
| 24 | 234386152841716303616 |
[1,1,1,4,8,38,206,1200,6824,50912,446752,3828592, 38953680,411358960,4740541440,57933236928, 759535226432,10488778719488,156933187370432, 2425018017191040,40031753222399360, 689218695990369536,12461424512466701312, 234386152841716303616] |