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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 32 |
| 4 | 258 |
| 5 | 1232 |
| 6 | 10291 |
| 7 | 48826 |
| 8 | 405404 |
| 9 | 1922824 |
| 10 | 15957927 |
| 11 | 75674424 |
| 12 | 627937288 |
| 13 | 2977619007 |
| 14 | 24707220314 |
| 15 | 117158008335 |
| 16 | 972128626445 |
| 17 | 4609679165199 |
| 18 | 38249153789915 |
| 19 | 181371291266288 |
| 20 | 1504941221689915 |
| 21 | 7136186544470695 |
[1,7,32,258,1232,10291,48826,405404,1922824, 15957927,75674424,627937288,2977619007, 24707220314,117158008335,972128626445, 4609679165199,38249153789915,181371291266288, 1504941221689915,7136186544470695] |