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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 6 |
| 6 | 17 |
| 7 | 79 |
| 8 | 330 |
| 9 | 1594 |
| 10 | 7876 |
| 11 | 41433 |
| 12 | 226617 |
| 13 | 1292848 |
| 14 | 7648771 |
| 15 | 46853853 |
| 16 | 296445440 |
| 17 | 1934035905 |
| 18 | 12990201995 |
| 19 | 89704403890 |
| 20 | 636105618633 |
| 21 | 4626864097514 |
| 22 | 34486708824384 |
| 23 | 263162984884732 |
| 24 | 2054168834202029 |
| 25 | 16388599312054049 |
[1,1,0,1,1,6,17,79,330,1594,7876,41433,226617, 1292848,7648771,46853853,296445440,1934035905, 12990201995,89704403890,636105618633, 4626864097514,34486708824384,263162984884732, 2054168834202029,16388599312054049] |