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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 10 |
| 3 | 80 |
| 4 | 610 |
| 5 | 4625 |
| 6 | 35322 |
| 7 | 272800 |
| 8 | 2132310 |
| 9 | 16861455 |
| 10 | 134781350 |
| 11 | 1088074064 |
| 12 | 8863227100 |
| 13 | 72789560025 |
| 14 | 602232150810 |
| 15 | 5016320750400 |
| 16 | 42041168169712 |
| 17 | 354326295908580 |
| 18 | 3001705818071400 |
| 19 | 25549873091193600 |
| 20 | 218426240780417250 |
| 21 | 1874878554813727815 |
| 22 | 16153461053030605590 |
[1,10,80,610,4625,35322,272800,2132310,16861455, 134781350,1088074064,8863227100,72789560025, 602232150810,5016320750400,42041168169712, 354326295908580,3001705818071400, 25549873091193600,218426240780417250, 1874878554813727815,16153461053030605590] |