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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 8 |
| 4 | 17 |
| 5 | 46 |
| 6 | 114 |
| 7 | 289 |
| 8 | 757 |
| 9 | 1964 |
| 10 | 5118 |
| 11 | 13391 |
| 12 | 35008 |
| 13 | 91589 |
| 14 | 239740 |
| 15 | 627506 |
| 16 | 1642656 |
| 17 | 4300361 |
| 18 | 11258087 |
| 19 | 29473546 |
| 20 | 77162161 |
| 21 | 202011991 |
| 22 | 528872756 |
| 23 | 1384604934 |
| 24 | 3624939359 |
| 25 | 9490209947 |
| 26 | 24845686106 |
| 27 | 65046840605 |
| 28 | 170294825972 |
[1,4,8,17,46,114,289,757,1964,5118,13391,35008, 91589,239740,627506,1642656,4300361,11258087, 29473546,77162161,202011991,528872756,1384604934, 3624939359,9490209947,24845686106,65046840605, 170294825972] |