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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 12 |
| 3 | 61 |
| 4 | 316 |
| 5 | 1304 |
| 6 | 5223 |
| 7 | 21557 |
| 8 | 90404 |
| 9 | 377863 |
| 10 | 1572942 |
| 11 | 6545785 |
| 12 | 27262279 |
| 13 | 113572619 |
| 14 | 473082153 |
| 15 | 1970443556 |
| 16 | 8207168564 |
| 17 | 34184621296 |
| 18 | 142386794787 |
| 19 | 593071821262 |
| 20 | 2470268797246 |
| 21 | 10289192009129 |
| 22 | 42856677944829 |
| 23 | 178507203892808 |
| 24 | 743520516941183 |
[4,12,61,316,1304,5223,21557,90404,377863,1572942, 6545785,27262279,113572619,473082153,1970443556, 8207168564,34184621296,142386794787,593071821262, 2470268797246,10289192009129,42856677944829, 178507203892808,743520516941183] |