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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1026 |
| 3 | 59052 |
| 4 | 1050628 |
| 5 | 9765630 |
| 6 | 60587352 |
| 7 | 282475256 |
| 8 | 1075843080 |
| 9 | 3486961557 |
| 10 | 10019536380 |
| 11 | 25937424612 |
| 12 | 62041684656 |
| 13 | 137858491862 |
| 14 | 289819612656 |
| 15 | 576679982760 |
| 16 | 1101663313936 |
| 17 | 2015993900466 |
| 18 | 3577622557482 |
| 19 | 6131066257820 |
| 20 | 10260044315640 |
[0,1,1026,59052,1050628,9765630,60587352, 282475256,1075843080,3486961557,10019536380, 25937424612,62041684656,137858491862,289819612656, 576679982760,1101663313936,2015993900466, 3577622557482,6131066257820,10260044315640] |