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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 19 |
| 5 | 54 |
| 6 | 183 |
| 7 | 632 |
| 8 | 2307 |
| 9 | 8753 |
| 10 | 34000 |
| 11 | 135893 |
| 12 | 552498 |
| 13 | 2288861 |
| 14 | 9619432 |
| 15 | 40955833 |
| 16 | 176439889 |
| 17 | 767614597 |
| 18 | 3370686080 |
| 19 | 14919375855 |
| 20 | 66519132927 |
| 21 | 298537169659 |
| 22 | 1347748022530 |
| 23 | 6117531357164 |
| 24 | 27904394951401 |
| 25 | 127858017889598 |
| 26 | 588274930715447 |
| 27 | 2716966368936216 |
| 28 | 12592645826466517 |
[1,1,3,6,19,54,183,632,2307,8753,34000,135893, 552498,2288861,9619432,40955833,176439889, 767614597,3370686080,14919375855,66519132927, 298537169659,1347748022530,6117531357164, 27904394951401,127858017889598,588274930715447, 2716966368936216,12592645826466517] |