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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 20 |
| 2 | 160 |
| 3 | 820 |
| 4 | 3190 |
| 5 | 10252 |
| 6 | 28600 |
| 7 | 71500 |
| 8 | 163735 |
| 9 | 348920 |
| 10 | 700128 |
| 11 | 1334840 |
| 12 | 2435420 |
| 13 | 4276520 |
| 14 | 7261040 |
| 15 | 11966504 |
| 16 | 19203965 |
| 17 | 30091820 |
| 18 | 46147200 |
| 19 | 69397900 |
| 20 | 102518130 |
| 21 | 148991700 |
| 22 | 213306600 |
| 23 | 301185300 |
[1,20,160,820,3190,10252,28600,71500,163735, 348920,700128,1334840,2435420,4276520,7261040, 11966504,19203965,30091820,46147200,69397900, 102518130,148991700,213306600,301185300] |