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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 42 |
| 3 | 594 |
| 4 | 4719 |
| 5 | 26026 |
| 6 | 111384 |
| 7 | 395352 |
| 8 | 1215126 |
| 9 | 3331251 |
| 10 | 8321170 |
| 11 | 19240650 |
| 12 | 41683005 |
| 13 | 85408596 |
| 14 | 166768096 |
| 15 | 312203232 |
| 16 | 563178924 |
| 17 | 982981701 |
| 18 | 1665911754 |
| 19 | 2749500754 |
| 20 | 4430505387 |
| 21 | 6985558206 |
| 22 | 10797503640 |
| 23 | 16388608600 |
| 24 | 24462014850 |
| 25 | 35952994935 |
| 26 | 52091785746 |
[0,1,42,594,4719,26026,111384,395352,1215126, 3331251,8321170,19240650,41683005,85408596, 166768096,312203232,563178924,982981701, 1665911754,2749500754,4430505387,6985558206, 10797503640,16388608600,24462014850,35952994935, 52091785746] |