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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 34 |
| 5 | 94 |
| 6 | 298 |
| 7 | 862 |
| 8 | 2650 |
| 9 | 7822 |
| 10 | 23722 |
| 11 | 70654 |
| 12 | 212986 |
| 13 | 636910 |
| 14 | 1914826 |
| 15 | 5736286 |
| 16 | 17225242 |
| 17 | 51642958 |
| 18 | 154994410 |
| 19 | 464852158 |
| 20 | 1394818618 |
| 21 | 4183931566 |
| 22 | 12552843274 |
| 23 | 37656432670 |
| 24 | 112973492314 |
| 25 | 338912088334 |
| 26 | 1016753042218 |
[0,1,4,10,34,94,298,862,2650,7822,23722,70654, 212986,636910,1914826,5736286,17225242,51642958, 154994410,464852158,1394818618,4183931566, 12552843274,37656432670,112973492314,338912088334, 1016753042218] |