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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 16 |
| 3 | 118 |
| 4 | 1004 |
| 5 | 8601 |
| 6 | 75076 |
| 7 | 662796 |
| 8 | 5903676 |
| 9 | 52949332 |
| 10 | 477533356 |
| 11 | 4326309406 |
| 12 | 39343725716 |
| 13 | 358943047438 |
| 14 | 3283745710968 |
| 15 | 30112624408488 |
| 16 | 276715616909148 |
| 17 | 2547523969430508 |
| 18 | 23491659440021920 |
| 19 | 216942761366305144 |
| 20 | 2006084011596742384 |
| 21 | 18572529488934397689 |
[1,1,16,118,1004,8601,75076,662796,5903676, 52949332,477533356,4326309406,39343725716, 358943047438,3283745710968,30112624408488, 276715616909148,2547523969430508, 23491659440021920,216942761366305144, 2006084011596742384,18572529488934397689] |