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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 11 |
| 4 | 70 |
| 5 | 503 |
| 6 | 3864 |
| 7 | 31092 |
| 8 | 258654 |
| 9 | 2206655 |
| 10 | 19200610 |
| 11 | 169739843 |
| 12 | 1520241320 |
| 13 | 13764959908 |
| 14 | 125792608400 |
| 15 | 1158745944312 |
| 16 | 10747830197070 |
| 17 | 100295912869263 |
| 18 | 940958196049830 |
| 19 | 8870071185895425 |
| 20 | 83972749650989430 |
| 21 | 798033019890224415 |
| 22 | 7610570090722324320 |
| 23 | 72810031747355657040 |
[1,2,11,70,503,3864,31092,258654,2206655,19200610, 169739843,1520241320,13764959908,125792608400, 1158745944312,10747830197070,100295912869263, 940958196049830,8870071185895425, 83972749650989430,798033019890224415, 7610570090722324320,72810031747355657040] |