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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 10 |
| 3 | 22 |
| 4 | 54 |
| 5 | 134 |
| 6 | 340 |
| 7 | 872 |
| 8 | 2254 |
| 9 | 5854 |
| 10 | 15250 |
| 11 | 39802 |
| 12 | 104004 |
| 13 | 271964 |
| 14 | 711490 |
| 15 | 1861862 |
| 16 | 4873054 |
| 17 | 12755614 |
| 18 | 33391060 |
| 19 | 87413152 |
| 20 | 228841254 |
| 21 | 599099054 |
| 22 | 1568437210 |
| 23 | 4106182322 |
| 24 | 10750060804 |
| 25 | 28143920884 |
| 26 | 73681573690 |
| 27 | 192900592822 |
| 28 | 505019869254 |
| 29 | 1322158472054 |
[1,4,10,22,54,134,340,872,2254,5854,15250,39802, 104004,271964,711490,1861862,4873054,12755614, 33391060,87413152,228841254,599099054,1568437210, 4106182322,10750060804,28143920884,73681573690, 192900592822,505019869254,1322158472054] |