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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 15 |
| 7 | 175 |
| 8 | 1960 |
| 9 | 22449 |
| 10 | 269577 |
| 11 | 3430790 |
| 12 | 46480830 |
| 13 | 671260876 |
| 14 | 10329270952 |
| 15 | 169125055736 |
| 16 | 2940784282800 |
| 17 | 54182845939104 |
| 18 | 1055291277366108 |
| 19 | 21674715826211532 |
| 20 | 468366193441002564 |
| 21 | 10624074081842024496 |
| 22 | 252432685158931968768 |
| 23 | 6270222495850552958004 |
[1,0,0,0,0,1,15,175,1960,22449,269577,3430790, 46480830,671260876,10329270952,169125055736, 2940784282800,54182845939104,1055291277366108, 21674715826211532,468366193441002564, 10624074081842024496,252432685158931968768, 6270222495850552958004] |