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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 10 |
| 2 | 25 |
| 3 | 63 |
| 4 | 159 |
| 5 | 401 |
| 6 | 1011 |
| 7 | 2549 |
| 8 | 6427 |
| 9 | 16205 |
| 10 | 40859 |
| 11 | 103021 |
| 12 | 259755 |
| 13 | 654941 |
| 14 | 1651355 |
| 15 | 4163693 |
| 16 | 10498251 |
| 17 | 26470077 |
| 18 | 66741115 |
| 19 | 168279693 |
| 20 | 424297003 |
| 21 | 1069813853 |
| 22 | 2697406939 |
| 23 | 6801187117 |
| 24 | 17148375179 |
| 25 | 43237565181 |
| 26 | 109018319419 |
| 27 | 274876578253 |
| 28 | 693068226283 |
[4,10,25,63,159,401,1011,2549,6427,16205,40859, 103021,259755,654941,1651355,4163693,10498251, 26470077,66741115,168279693,424297003,1069813853, 2697406939,6801187117,17148375179,43237565181, 109018319419,274876578253,693068226283] |