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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 28 |
| 4 | 200 |
| 5 | 1532 |
| 6 | 11794 |
| 7 | 90538 |
| 8 | 695252 |
| 9 | 5339294 |
| 10 | 41003018 |
| 11 | 314882364 |
| 12 | 2418138526 |
| 13 | 18570087298 |
| 14 | 142608927356 |
| 15 | 1095164819630 |
| 16 | 8410314860218 |
| 17 | 64586987065356 |
| 18 | 495995568270926 |
| 19 | 3808996439085090 |
| 20 | 29251176423848812 |
[0,3,28,200,1532,11794,90538,695252,5339294, 41003018,314882364,2418138526,18570087298, 142608927356,1095164819630,8410314860218, 64586987065356,495995568270926,3808996439085090, 29251176423848812] |