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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 0 |
| 5 | 0 |
| 6 | 15 |
| 7 | 0 |
| 8 | 0 |
| 9 | 1540 |
| 10 | 3150 |
| 11 | 24255 |
| 12 | 81235 |
| 13 | 496210 |
| 14 | 605605 |
| 15 | 36987951 |
| 16 | 13833820 |
| 17 | 849333940 |
| 18 | 24419945732 |
| 19 | 111237098546 |
| 20 | 1219799147204 |
| 21 | 16146398449224 |
| 22 | 109697049177254 |
| 23 | 1037441240056529 |
| 24 | 9042707959752775 |
| 25 | 84237798887033660 |
| 26 | 614681985047225810 |
[1,0,0,15,0,0,1540,3150,24255,81235,496210,605605, 36987951,13833820,849333940,24419945732, 111237098546,1219799147204,16146398449224, 109697049177254,1037441240056529,9042707959752775, 84237798887033660,614681985047225810] |