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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 58 |
| 5 | 226 |
| 6 | 1055 |
| 7 | 4519 |
| 8 | 21614 |
| 9 | 97094 |
| 10 | 471010 |
| 11 | 2178613 |
| 12 | 10660517 |
| 13 | 50257832 |
| 14 | 247314696 |
| 15 | 1181334243 |
| 16 | 5835644820 |
| 17 | 28137910424 |
| 18 | 139376200116 |
| 19 | 676714986878 |
| 20 | 3358628183403 |
| 21 | 16393168567510 |
| 22 | 81481596697479 |
| 23 | 399325900478770 |
| 24 | 1987060483010033 |
| 25 | 9769457634905532 |
| 26 | 48655357050063238 |
| 27 | 239829359080746283 |
[1,1,4,13,58,226,1055,4519,21614,97094,471010, 2178613,10660517,50257832,247314696,1181334243, 5835644820,28137910424,139376200116,676714986878, 3358628183403,16393168567510,81481596697479, 399325900478770,1987060483010033,9769457634905532, 48655357050063238,239829359080746283] |