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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 20 |
| 3 | 428 |
| 4 | 17110 |
| 5 | 1091766 |
| 6 | 101766250 |
| 7 | 13040248694 |
| 8 | 2198098221276 |
| 9 | 471419186556726 |
| 10 | 125322878397310538 |
| 11 | 40439205050500365772 |
| 12 | 15568170274714608264574 |
| 13 | 7048162234159021690430456 |
[2,20,428,17110,1091766,101766250,13040248694, 2198098221276,471419186556726,125322878397310538, 40439205050500365772,15568170274714608264574, 7048162234159021690430456] |