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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 31 |
| 6 | 111 |
| 7 | 415 |
| 8 | 1591 |
| 9 | 6229 |
| 10 | 24773 |
| 11 | 99793 |
| 12 | 406197 |
| 13 | 1667803 |
| 14 | 6898183 |
| 15 | 28710933 |
| 16 | 120146889 |
| 17 | 505161063 |
| 18 | 2132805899 |
| 19 | 9037954725 |
| 20 | 38424844083 |
| 21 | 163843435737 |
| 22 | 700477124863 |
| 23 | 3001906536983 |
| 24 | 12892683275989 |
| 25 | 55481600408439 |
| 26 | 239188767723227 |
| 27 | 1032889415516779 |
[1,1,3,9,31,111,415,1591,6229,24773,99793,406197, 1667803,6898183,28710933,120146889,505161063, 2132805899,9037954725,38424844083,163843435737, 700477124863,3001906536983,12892683275989, 55481600408439,239188767723227,1032889415516779] |