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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 10 |
| 3 | 26 |
| 4 | 77 |
| 5 | 235 |
| 6 | 779 |
| 7 | 2785 |
| 8 | 10643 |
| 9 | 43697 |
| 10 | 192893 |
| 11 | 915218 |
| 12 | 4657929 |
| 13 | 25380749 |
| 14 | 147721169 |
| 15 | 916036271 |
| 16 | 6037442989 |
| 17 | 42191467826 |
| 18 | 311911160465 |
| 19 | 2434014941905 |
| 20 | 20007995450483 |
| 21 | 172911791611798 |
| 22 | 1568190042677867 |
[1,4,10,26,77,235,779,2785,10643,43697,192893, 915218,4657929,25380749,147721169,916036271, 6037442989,42191467826,311911160465,2434014941905, 20007995450483,172911791611798,1568190042677867] |