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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 55 |
| 3 | 868 |
| 4 | 13825 |
| 5 | 220324 |
| 6 | 3511351 |
| 7 | 55961284 |
| 8 | 891869185 |
| 9 | 14213945668 |
| 10 | 226531261495 |
| 11 | 3610286238244 |
| 12 | 57538048550401 |
| 13 | 916998490568164 |
| 14 | 14614437800540215 |
| 15 | 232914006318075268 |
| 16 | 3712009663288664065 |
[1,4,55,868,13825,220324,3511351,55961284, 891869185,14213945668,226531261495,3610286238244, 57538048550401,916998490568164,14614437800540215, 232914006318075268,3712009663288664065] |