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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 19 |
| 6 | 135 |
| 7 | 1204 |
| 8 | 12537 |
| 9 | 150556 |
| 10 | 2043930 |
| 11 | 30969211 |
| 12 | 517973148 |
| 13 | 9478800604 |
| 14 | 188381470095 |
| 15 | 4040440921699 |
| 16 | 93020386382742 |
| 17 | 2287969523647171 |
| 18 | 59877222907995675 |
| 19 | 1661259526266784171 |
| 20 | 48705364034046758493 |
| 21 | 1504614657169716311674 |
| 22 | 48848750173492332588525 |
[1,0,1,3,19,135,1204,12537,150556,2043930, 30969211,517973148,9478800604,188381470095, 4040440921699,93020386382742,2287969523647171, 59877222907995675,1661259526266784171, 48705364034046758493,1504614657169716311674, 48848750173492332588525] |