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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 102 |
| 5 | 414 |
| 6 | 1805 |
| 7 | 7815 |
| 8 | 35323 |
| 9 | 158644 |
| 10 | 733072 |
| 11 | 3369245 |
| 12 | 15799972 |
| 13 | 73770858 |
| 14 | 349586259 |
| 15 | 1650776523 |
| 16 | 7883670078 |
| 17 | 37542772998 |
| 18 | 180365623658 |
| 19 | 864515802872 |
| 20 | 4172921778396 |
| 21 | 20104175611203 |
| 22 | 97408657759242 |
| 23 | 471235087095606 |
| 24 | 2290330542518136 |
| 25 | 11117532170213077 |
| 26 | 54174311113381971 |
| 27 | 263709713662432669 |
[1,2,7,25,102,414,1805,7815,35323,158644,733072, 3369245,15799972,73770858,349586259,1650776523, 7883670078,37542772998,180365623658,864515802872, 4172921778396,20104175611203,97408657759242, 471235087095606,2290330542518136, 11117532170213077,54174311113381971, 263709713662432669] |