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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 28 |
| 3 | 98 |
| 4 | 350 |
| 5 | 1274 |
| 6 | 4706 |
| 7 | 17576 |
| 8 | 66196 |
| 9 | 250952 |
| 10 | 956384 |
| 11 | 3660540 |
| 12 | 14061140 |
| 13 | 54177740 |
| 14 | 209295260 |
| 15 | 810375650 |
| 16 | 3143981870 |
| 17 | 12219117170 |
| 18 | 47564380970 |
| 19 | 185410909790 |
| 20 | 723668784230 |
| 21 | 2827767747950 |
| 22 | 11061198475550 |
| 23 | 43308802158650 |
| 24 | 169719408596402 |
| 25 | 665637941544506 |
[1,8,28,98,350,1274,4706,17576,66196,250952, 956384,3660540,14061140,54177740,209295260, 810375650,3143981870,12219117170,47564380970, 185410909790,723668784230,2827767747950, 11061198475550,43308802158650,169719408596402, 665637941544506] |