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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 6 |
| 6 | 37 |
| 7 | 183 |
| 8 | 877 |
| 9 | 3930 |
| 10 | 17185 |
| 11 | 73095 |
| 12 | 306361 |
| 13 | 1267266 |
| 14 | 5198557 |
| 15 | 21182343 |
| 16 | 85910917 |
| 17 | 347187210 |
| 18 | 1399451545 |
| 19 | 5629911015 |
| 20 | 22616256721 |
| 21 | 90754855026 |
| 22 | 363890126677 |
| 23 | 1458172596903 |
| 24 | 5840531635357 |
| 25 | 23385650196090 |
[0,0,0,1,6,37,183,877,3930,17185,73095,306361, 1267266,5198557,21182343,85910917,347187210, 1399451545,5629911015,22616256721,90754855026, 363890126677,1458172596903,5840531635357, 23385650196090] |