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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1026 |
| 3 | 60077 |
| 4 | 1110704 |
| 5 | 10936407 |
| 6 | 72573360 |
| 7 | 365983991 |
| 8 | 1513288698 |
| 9 | 5365004410 |
| 10 | 16877063274 |
| 11 | 48105808222 |
| 12 | 126584890148 |
| 13 | 310963328163 |
| 14 | 721354362186 |
| 15 | 1590587613754 |
| 16 | 3359058693214 |
| 17 | 6822189191429 |
| 18 | 13396265918970 |
| 19 | 25501949210562 |
| 20 | 47248199227946 |
| 21 | 85355336473378 |
[0,1,1026,60077,1110704,10936407,72573360, 365983991,1513288698,5365004410,16877063274, 48105808222,126584890148,310963328163, 721354362186,1590587613754,3359058693214, 6822189191429,13396265918970,25501949210562, 47248199227946,85355336473378] |