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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 10 |
| 3 | 25 |
| 4 | 64 |
| 5 | 166 |
| 6 | 433 |
| 7 | 1132 |
| 8 | 2962 |
| 9 | 7753 |
| 10 | 20296 |
| 11 | 53134 |
| 12 | 139105 |
| 13 | 364180 |
| 14 | 953434 |
| 15 | 2496121 |
| 16 | 6534928 |
| 17 | 17108662 |
| 18 | 44791057 |
| 19 | 117264508 |
| 20 | 307002466 |
| 21 | 803742889 |
| 22 | 2104226200 |
| 23 | 5508935710 |
| 24 | 14422580929 |
| 25 | 37758807076 |
| 26 | 98853840298 |
| 27 | 258802713817 |
| 28 | 677554301152 |
[1,4,10,25,64,166,433,1132,2962,7753,20296,53134, 139105,364180,953434,2496121,6534928,17108662, 44791057,117264508,307002466,803742889,2104226200, 5508935710,14422580929,37758807076,98853840298, 258802713817,677554301152] |