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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 102 |
| 5 | 421 |
| 6 | 1835 |
| 7 | 8068 |
| 8 | 36463 |
| 9 | 165906 |
| 10 | 766789 |
| 11 | 3562740 |
| 12 | 16714944 |
| 13 | 78749841 |
| 14 | 373407046 |
| 15 | 1776555853 |
| 16 | 8490305807 |
| 17 | 40686783270 |
| 18 | 195617231802 |
| 19 | 942606575327 |
| 20 | 4553378965810 |
| 21 | 22036254471516 |
| 22 | 106852979603759 |
| 23 | 518923028545648 |
| 24 | 2524046047179717 |
| 25 | 12292867020315560 |
| 26 | 59946635460333394 |
| 27 | 292653126601321637 |
[1,2,7,25,102,421,1835,8068,36463,165906,766789, 3562740,16714944,78749841,373407046,1776555853, 8490305807,40686783270,195617231802,942606575327, 4553378965810,22036254471516,106852979603759, 518923028545648,2524046047179717, 12292867020315560,59946635460333394, 292653126601321637] |