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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 17 |
| 4 | 60 |
| 5 | 216 |
| 6 | 846 |
| 7 | 3378 |
| 8 | 13471 |
| 9 | 55966 |
| 10 | 235362 |
| 11 | 985219 |
| 12 | 4229588 |
| 13 | 18306710 |
| 14 | 78859172 |
| 15 | 345683311 |
| 16 | 1524069221 |
| 17 | 6691150026 |
| 18 | 29757260250 |
| 19 | 132901102923 |
| 20 | 591431979600 |
| 21 | 2658213887242 |
| 22 | 11986371888040 |
| 23 | 53884698804024 |
| 24 | 244154568785732 |
| 25 | 1109127744084492 |
| 26 | 5025475273411278 |
| 27 | 22916851970688849 |
[1,2,5,17,60,216,846,3378,13471,55966,235362, 985219,4229588,18306710,78859172,345683311, 1524069221,6691150026,29757260250,132901102923, 591431979600,2658213887242,11986371888040, 53884698804024,244154568785732,1109127744084492, 5025475273411278,22916851970688849] |