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| n | a(n) |
|---|---|
| 1 | 220 |
| 2 | 784 |
| 3 | 3108 |
| 4 | 12100 |
| 5 | 45684 |
| 6 | 174724 |
| 7 | 674856 |
| 8 | 2585664 |
| 9 | 9853288 |
| 10 | 37724164 |
| 11 | 144911780 |
| 12 | 555167844 |
| 13 | 2122710008 |
| 14 | 8128825600 |
| 15 | 31164354584 |
| 16 | 119371632004 |
| 17 | 456940637076 |
| 18 | 1750016785924 |
| 19 | 6704844968808 |
| 20 | 25680650841664 |
| 21 | 98339620401640 |
[220,784,3108,12100,45684,174724,674856,2585664, 9853288,37724164,144911780,555167844,2122710008, 8128825600,31164354584,119371632004,456940637076, 1750016785924,6704844968808,25680650841664, 98339620401640] |