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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 38 |
| 5 | 92 |
| 6 | 214 |
| 7 | 490 |
| 8 | 1108 |
| 9 | 2474 |
| 10 | 5462 |
| 11 | 11948 |
| 12 | 25942 |
| 13 | 55978 |
| 14 | 120148 |
| 15 | 256682 |
| 16 | 546134 |
| 17 | 1157804 |
| 18 | 2446678 |
| 19 | 5155498 |
| 20 | 10835284 |
| 21 | 22719146 |
| 22 | 47535446 |
| 23 | 99265196 |
| 24 | 206918998 |
| 25 | 430615210 |
| 26 | 894784852 |
| 27 | 1856678570 |
| 28 | 3847574870 |
| 29 | 7963585196 |
[1,1,4,14,38,92,214,490,1108,2474,5462,11948, 25942,55978,120148,256682,546134,1157804,2446678, 5155498,10835284,22719146,47535446,99265196, 206918998,430615210,894784852,1856678570, 3847574870,7963585196] |