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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 36 |
| 4 | 160 |
| 5 | 716 |
| 6 | 3314 |
| 7 | 15388 |
| 8 | 72499 |
| 9 | 342935 |
| 10 | 1635960 |
| 11 | 7824257 |
| 12 | 37611809 |
| 13 | 181209322 |
| 14 | 876049115 |
| 15 | 4242706707 |
| 16 | 20596344336 |
| 17 | 100135723710 |
| 18 | 487704113642 |
| 19 | 2378266514902 |
| 20 | 11613225600136 |
| 21 | 56767518355194 |
| 22 | 277790357624818 |
| 23 | 1360560956453716 |
| 24 | 6669645937906914 |
| 25 | 32720231458322324 |
| 26 | 160639177418874272 |
[1,2,9,36,160,716,3314,15388,72499,342935,1635960, 7824257,37611809,181209322,876049115,4242706707, 20596344336,100135723710,487704113642, 2378266514902,11613225600136,56767518355194, 277790357624818,1360560956453716,6669645937906914, 32720231458322324,160639177418874272] |