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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 8 |
| 3 | 31 |
| 4 | 90 |
| 5 | 225 |
| 6 | 516 |
| 7 | 1123 |
| 8 | 2366 |
| 9 | 4885 |
| 10 | 9960 |
| 11 | 20151 |
| 12 | 40578 |
| 13 | 81481 |
| 14 | 163340 |
| 15 | 327115 |
| 16 | 654726 |
| 17 | 1310013 |
| 18 | 2620656 |
| 19 | 5242015 |
| 20 | 10484810 |
| 21 | 20970481 |
| 22 | 41941908 |
| 23 | 83884851 |
| 24 | 167770830 |
| 25 | 335542885 |
| 26 | 671087096 |
| 27 | 1342175623 |
| 28 | 2684352786 |
[1,8,31,90,225,516,1123,2366,4885,9960,20151, 40578,81481,163340,327115,654726,1310013,2620656, 5242015,10484810,20970481,41941908,83884851, 167770830,335542885,671087096,1342175623, 2684352786] |