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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 3 |
| 8 | 9 |
| 9 | 28 |
| 10 | 75 |
| 11 | 195 |
| 12 | 498 |
| 13 | 1229 |
| 14 | 2978 |
| 15 | 7115 |
| 16 | 16756 |
| 17 | 39031 |
| 18 | 90089 |
| 19 | 206228 |
| 20 | 468795 |
| 21 | 1059197 |
| 22 | 2380257 |
| 23 | 5323610 |
| 24 | 11856514 |
| 25 | 26306896 |
| 26 | 58172254 |
| 27 | 128246136 |
| 28 | 281957282 |
| 29 | 618367332 |
| 30 | 1353112803 |
[0,0,0,0,0,0,1,3,9,28,75,195,498,1229,2978,7115, 16756,39031,90089,206228,468795,1059197,2380257, 5323610,11856514,26306896,58172254,128246136, 281957282,618367332,1353112803] |