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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 76 |
| 6 | 267 |
| 7 | 932 |
| 8 | 3263 |
| 9 | 11410 |
| 10 | 40028 |
| 11 | 140955 |
| 12 | 498467 |
| 13 | 1769249 |
| 14 | 6299282 |
| 15 | 22485487 |
| 16 | 80435919 |
| 17 | 288275461 |
| 18 | 1034862558 |
| 19 | 3720499175 |
| 20 | 13393720428 |
| 21 | 48275699654 |
| 22 | 174194970601 |
| 23 | 629187941167 |
| 24 | 2274710068067 |
| 25 | 8230764250326 |
| 26 | 29805342037721 |
| 27 | 108009638665648 |
[1,1,3,7,23,76,267,932,3263,11410,40028,140955, 498467,1769249,6299282,22485487,80435919, 288275461,1034862558,3720499175,13393720428, 48275699654,174194970601,629187941167, 2274710068067,8230764250326,29805342037721, 108009638665648] |