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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 52 |
| 5 | 190 |
| 6 | 760 |
| 7 | 2911 |
| 8 | 11644 |
| 9 | 45526 |
| 10 | 182104 |
| 11 | 719158 |
| 12 | 2876632 |
| 13 | 11420476 |
| 14 | 45681904 |
| 15 | 181897393 |
| 16 | 727589572 |
| 17 | 2902122838 |
| 18 | 11608491352 |
| 19 | 46350498442 |
| 20 | 185401993768 |
| 21 | 740747412928 |
| 22 | 2962989651712 |
| 23 | 11842961166202 |
| 24 | 47371844664808 |
| 25 | 189392208541144 |
| 26 | 757568834164576 |
| 27 | 3029258755839088 |
[1,1,4,13,52,190,760,2911,11644,45526,182104, 719158,2876632,11420476,45681904,181897393, 727589572,2902122838,11608491352,46350498442, 185401993768,740747412928,2962989651712, 11842961166202,47371844664808,189392208541144, 757568834164576,3029258755839088] |