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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 12 |
| 4 | 37 |
| 5 | 114 |
| 6 | 335 |
| 7 | 1003 |
| 8 | 3051 |
| 9 | 9290 |
| 10 | 28268 |
| 11 | 86013 |
| 12 | 261786 |
| 13 | 796995 |
| 14 | 2426793 |
| 15 | 7389825 |
| 16 | 22503304 |
| 17 | 68527674 |
| 18 | 208684983 |
| 19 | 635506294 |
| 20 | 1935309489 |
| 21 | 5893618625 |
| 22 | 17947924171 |
| 23 | 54657124744 |
| 24 | 166448373086 |
| 25 | 506888519813 |
| 26 | 1543637889196 |
[1,4,12,37,114,335,1003,3051,9290,28268,86013, 261786,796995,2426793,7389825,22503304,68527674, 208684983,635506294,1935309489,5893618625, 17947924171,54657124744,166448373086,506888519813, 1543637889196] |