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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 30 |
| 6 | 101 |
| 7 | 325 |
| 8 | 1173 |
| 9 | 4129 |
| 10 | 15600 |
| 11 | 57991 |
| 12 | 227819 |
| 13 | 882158 |
| 14 | 3556595 |
| 15 | 14196649 |
| 16 | 58341251 |
| 17 | 237985861 |
| 18 | 994094162 |
| 19 | 4126639959 |
| 20 | 17456975753 |
| 21 | 73516604930 |
| 22 | 314208829825 |
| 23 | 1338355571447 |
| 24 | 5771924502800 |
| 25 | 24822352236154 |
| 26 | 107856520063495 |
| 27 | 467688123042216 |
| 28 | 2045200218407310 |
| 29 | 8929933841268928 |
[1,1,2,4,11,30,101,325,1173,4129,15600,57991, 227819,882158,3556595,14196649,58341251,237985861, 994094162,4126639959,17456975753,73516604930, 314208829825,1338355571447,5771924502800, 24822352236154,107856520063495,467688123042216, 2045200218407310,8929933841268928] |