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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 22 |
| 4 | 58 |
| 5 | 158 |
| 6 | 420 |
| 7 | 1136 |
| 8 | 3036 |
| 9 | 8180 |
| 10 | 21920 |
| 11 | 58952 |
| 12 | 158168 |
| 13 | 425032 |
| 14 | 1140976 |
| 15 | 3064960 |
| 16 | 8229648 |
| 17 | 22103600 |
| 18 | 59355776 |
| 19 | 159410272 |
| 20 | 428089760 |
| 21 | 1149677536 |
| 22 | 3087468096 |
| 23 | 8291603712 |
| 24 | 22267339200 |
| 25 | 59800139584 |
| 26 | 160595513856 |
| 27 | 431286986880 |
| 28 | 1158238963072 |
[1,3,8,22,58,158,420,1136,3036,8180,21920,58952, 158168,425032,1140976,3064960,8229648,22103600, 59355776,159410272,428089760,1149677536, 3087468096,8291603712,22267339200,59800139584, 160595513856,431286986880,1158238963072] |