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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 46 |
| 5 | 148 |
| 6 | 466 |
| 7 | 1468 |
| 8 | 4630 |
| 9 | 14596 |
| 10 | 46018 |
| 11 | 145084 |
| 12 | 457414 |
| 13 | 1442116 |
| 14 | 4546642 |
| 15 | 14334460 |
| 16 | 45193078 |
| 17 | 142482820 |
| 18 | 449213794 |
| 19 | 1416262204 |
| 20 | 4465131430 |
| 21 | 14077477060 |
| 22 | 44382872818 |
| 23 | 139928439676 |
| 24 | 441160451926 |
| 25 | 1390871968516 |
| 26 | 4385082172162 |
| 27 | 13825101153724 |
[1,4,16,46,148,466,1468,4630,14596,46018,145084, 457414,1442116,4546642,14334460,45193078, 142482820,449213794,1416262204,4465131430, 14077477060,44382872818,139928439676,441160451926, 1390871968516,4385082172162,13825101153724] |