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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 19 |
| 5 | 73 |
| 6 | 292 |
| 7 | 1203 |
| 8 | 5065 |
| 9 | 21697 |
| 10 | 94274 |
| 11 | 414514 |
| 12 | 1840981 |
| 13 | 8247011 |
| 14 | 37220261 |
| 15 | 169079113 |
| 16 | 772489020 |
| 17 | 3547371679 |
| 18 | 16364309243 |
| 19 | 75799327800 |
| 20 | 352402156770 |
| 21 | 1643878188646 |
| 22 | 7691841654538 |
| 23 | 36091803172733 |
[1,0,1,5,19,73,292,1203,5065,21697,94274,414514, 1840981,8247011,37220261,169079113,772489020, 3547371679,16364309243,75799327800,352402156770, 1643878188646,7691841654538,36091803172733] |