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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 5 |
| 6 | 81 |
| 7 | 658 |
| 8 | 3830 |
| 9 | 18525 |
| 10 | 80587 |
| 11 | 330330 |
| 12 | 1312015 |
| 13 | 5132075 |
| 14 | 19946915 |
| 15 | 77383374 |
| 16 | 300272554 |
| 17 | 1166405717 |
| 18 | 4536991655 |
| 19 | 17671814690 |
| 20 | 68922126879 |
| 21 | 269127380699 |
| 22 | 1052047384687 |
| 23 | 4116712577510 |
| 24 | 16123798186665 |
| 25 | 63205298480275 |
| 26 | 247959260395901 |
| 27 | 973469705104278 |
[0,0,0,0,5,81,658,3830,18525,80587,330330,1312015, 5132075,19946915,77383374,300272554,1166405717, 4536991655,17671814690,68922126879,269127380699, 1052047384687,4116712577510,16123798186665, 63205298480275,247959260395901,973469705104278] |