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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 17 |
| 6 | 74 |
| 7 | 300 |
| 8 | 1755 |
| 9 | 9360 |
| 10 | 65510 |
| 11 | 442117 |
| 12 | 3802889 |
| 13 | 30213386 |
| 14 | 294892947 |
| 15 | 2789021105 |
| 16 | 31360525517 |
| 17 | 334374848070 |
| 18 | 4184958056248 |
| 19 | 50606351991305 |
| 20 | 704124800141153 |
| 21 | 9452367941048830 |
| 22 | 143309007303310536 |
| 23 | 2124982437997726705 |
| 24 | 35389562541842450218 |
[1,1,2,6,17,74,300,1755,9360,65510,442117,3802889, 30213386,294892947,2789021105,31360525517, 334374848070,4184958056248,50606351991305, 704124800141153,9452367941048830, 143309007303310536,2124982437997726705, 35389562541842450218] |