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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 70 |
| 4 | 700229 |
| 5 | 184239362390740969 |
| 6 | 3620071869990730348276861702715495626355546 |
| 7 | 1397856755476623081643981198354119089406016417825924278115794483751825503676804770385912700712220 |
[2,6,70,700229,184239362390740969, 3620071869990730348276861702715495626355546, 13978567554766230816439811983541190894060164178259\ 24278115794483751825503676804770385912700712220] |