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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 37 |
| 6 | 168 |
| 7 | 895 |
| 8 | 5097 |
| 9 | 30983 |
| 10 | 196096 |
| 11 | 1283552 |
| 12 | 8621364 |
| 13 | 59176966 |
| 14 | 413613891 |
| 15 | 2936303012 |
| 16 | 21128390679 |
| 17 | 153841228779 |
| 18 | 1131941424480 |
| 19 | 8406680733066 |
| 20 | 62958726953945 |
| 21 | 475074493277317 |
| 22 | 3609405128045162 |
| 23 | 27593870865196624 |
| 24 | 212159118489924538 |
| 25 | 1639760091688265416 |
[1,1,3,9,37,168,895,5097,30983,196096,1283552, 8621364,59176966,413613891,2936303012,21128390679, 153841228779,1131941424480,8406680733066, 62958726953945,475074493277317,3609405128045162, 27593870865196624,212159118489924538, 1639760091688265416] |