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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 38 |
| 3 | 395 |
| 4 | 3778 |
| 5 | 32126 |
| 6 | 261042 |
| 7 | 2095121 |
| 8 | 16773300 |
| 9 | 134209760 |
| 10 | 1073726672 |
| 11 | 8589906710 |
| 12 | 68719426436 |
| 13 | 549755721410 |
| 14 | 4398046339192 |
| 15 | 35184371768852 |
| 16 | 281474976122716 |
| 17 | 2251799812612122 |
| 18 | 18014398507523968 |
| 19 | 144115188072265072 |
[4,38,395,3778,32126,261042,2095121,16773300, 134209760,1073726672,8589906710,68719426436, 549755721410,4398046339192,35184371768852, 281474976122716,2251799812612122, 18014398507523968,144115188072265072] |