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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 80 |
| 6 | 776 |
| 7 | 8992 |
| 8 | 130768 |
| 9 | 2252672 |
| 10 | 43823872 |
| 11 | 957193856 |
| 12 | 23369928704 |
| 13 | 629680631296 |
| 14 | 18514472015872 |
| 15 | 590350181439488 |
| 16 | 20311856724176896 |
| 17 | 749913022501879808 |
| 18 | 29561045244530032640 |
| 19 | 1239353203580700000256 |
| 20 | 55077035791625925492736 |
| 21 | 2586090541400666789543936 |
| 22 | 127922890235433583945056256 |
| 23 | 6649362432158408977810522112 |
| 24 | 362360171399316029979428126720 |
| 25 | 20658795751396952768159379619840 |
[1,1,2,10,80,776,8992,130768,2252672,43823872, 957193856,23369928704,629680631296,18514472015872, 590350181439488,20311856724176896, 749913022501879808,29561045244530032640, 1239353203580700000256,55077035791625925492736, 2586090541400666789543936, 127922890235433583945056256, 6649362432158408977810522112, 362360171399316029979428126720, 20658795751396952768159379619840] |