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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 14 |
| 3 | 46 |
| 4 | 136 |
| 5 | 382 |
| 6 | 1022 |
| 7 | 2626 |
| 8 | 6530 |
| 9 | 15784 |
| 10 | 37218 |
| 11 | 85842 |
| 12 | 194146 |
| 13 | 431358 |
| 14 | 943038 |
| 15 | 2031454 |
| 16 | 4316884 |
| 17 | 9058662 |
| 18 | 18787730 |
| 19 | 38542526 |
| 20 | 78264298 |
| 21 | 157403290 |
| 22 | 313712482 |
| 23 | 619919350 |
| 24 | 1215125262 |
| 25 | 2363570168 |
| 26 | 4563951858 |
| 27 | 8751621598 |
| 28 | 16670498062 |
| 29 | 31553539214 |
| 30 | 59361428202 |
[1,4,14,46,136,382,1022,2626,6530,15784,37218, 85842,194146,431358,943038,2031454,4316884, 9058662,18787730,38542526,78264298,157403290, 313712482,619919350,1215125262,2363570168, 4563951858,8751621598,16670498062,31553539214, 59361428202] |