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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 22 |
| 4 | 68 |
| 5 | 198 |
| 6 | 586 |
| 7 | 1718 |
| 8 | 5047 |
| 9 | 14808 |
| 10 | 43470 |
| 11 | 127636 |
| 12 | 374957 |
| 13 | 1102078 |
| 14 | 3241082 |
| 15 | 9537070 |
| 16 | 28079357 |
| 17 | 82718212 |
| 18 | 243809138 |
| 19 | 718994032 |
| 20 | 2121378272 |
| 21 | 6262089436 |
| 22 | 18493519148 |
| 23 | 54639914652 |
| 24 | 161503493023 |
| 25 | 477558890378 |
| 26 | 1412658185320 |
[1,2,8,22,68,198,586,1718,5047,14808,43470,127636, 374957,1102078,3241082,9537070,28079357,82718212, 243809138,718994032,2121378272,6262089436, 18493519148,54639914652,161503493023,477558890378, 1412658185320] |