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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 32 |
| 5 | 343 |
| 6 | 4505 |
| 7 | 66603 |
| 8 | 1045335 |
| 9 | 17115162 |
| 10 | 289107854 |
| 11 | 5007144433 |
| 12 | 88516438360 |
| 13 | 1591949961503 |
| 14 | 29053438148676 |
| 15 | 536972307386326 |
| 16 | 10034276171127780 |
| 17 | 189331187319203010 |
| 18 | 3603141751525175854 |
| 19 | 69097496637591215442 |
| 20 | 1334213677527481808220 |
| 21 | 25922717218623692348237 |
[1,1,1,5,32,343,4505,66603,1045335,17115162, 289107854,5007144433,88516438360,1591949961503, 29053438148676,536972307386326,10034276171127780, 189331187319203010,3603141751525175854, 69097496637591215442,1334213677527481808220, 25922717218623692348237] |