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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 10 |
| 3 | 55 |
| 4 | 670 |
| 5 | 4840 |
| 6 | 55252 |
| 7 | 436975 |
| 8 | 4816030 |
| 9 | 40051495 |
| 10 | 432457640 |
| 11 | 3715101654 |
| 12 | 39581170420 |
| 13 | 347847754670 |
| 14 | 3671331273480 |
| 15 | 32811494188975 |
| 16 | 343900019857310 |
| 17 | 3113537578058979 |
| 18 | 32458256583753952 |
| 19 | 296896918816556380 |
| 20 | 3081918923741896840 |
[1,10,55,670,4840,55252,436975,4816030,40051495, 432457640,3715101654,39581170420,347847754670, 3671331273480,32811494188975,343900019857310, 3113537578058979,32458256583753952, 296896918816556380,3081918923741896840] |