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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 104 |
| 6 | 552 |
| 7 | 3524 |
| 8 | 25832 |
| 9 | 194244 |
| 10 | 1645130 |
| 11 | 15475210 |
| 12 | 157548326 |
| 13 | 1768461238 |
| 14 | 20643856190 |
| 15 | 259156292058 |
| 16 | 3534238845228 |
[1,2,6,24,104,552,3524,25832,194244,1645130, 15475210,157548326,1768461238,20643856190, 259156292058,3534238845228] |