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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 5 |
| 7 | 12 |
| 8 | 25 |
| 9 | 57 |
| 10 | 128 |
| 11 | 296 |
| 12 | 688 |
| 13 | 1618 |
| 14 | 3839 |
| 15 | 9170 |
| 16 | 22065 |
| 17 | 53370 |
| 18 | 129807 |
| 19 | 317080 |
| 20 | 777887 |
| 21 | 1915247 |
| 22 | 4731932 |
| 23 | 11726476 |
| 24 | 29143123 |
| 25 | 72614115 |
| 26 | 181363151 |
| 27 | 453975928 |
| 28 | 1138697689 |
| 29 | 2861607677 |
| 30 | 7204169689 |
[1,0,1,1,3,5,12,25,57,128,296,688,1618,3839,9170, 22065,53370,129807,317080,777887,1915247,4731932, 11726476,29143123,72614115,181363151,453975928, 1138697689,2861607677,7204169689] |