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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 52 |
| 2 | 140452 |
| 3 | 2770663499604052 |
| 4 | 21269209556953516583554114034636483645584976452 |
[4,52,140452,2770663499604052, 21269209556953516583554114034636483645584976452] |