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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 44 |
| 4 | 210 |
| 5 | 935 |
| 6 | 4004 |
| 7 | 16744 |
| 8 | 68952 |
| 9 | 281010 |
| 10 | 1136960 |
| 11 | 4576264 |
| 12 | 18349630 |
| 13 | 73370115 |
| 14 | 292746300 |
| 15 | 1166182800 |
| 16 | 4639918800 |
| 17 | 18443677230 |
| 18 | 73261092240 |
| 19 | 290845019400 |
| 20 | 1154169552900 |
| 21 | 4578702310182 |
| 22 | 18159992594568 |
| 23 | 72014135814704 |
| 24 | 285542883894800 |
| 25 | 1132125641947300 |
[0,1,8,44,210,935,4004,16744,68952,281010,1136960, 4576264,18349630,73370115,292746300,1166182800, 4639918800,18443677230,73261092240,290845019400, 1154169552900,4578702310182,18159992594568, 72014135814704,285542883894800,1132125641947300] |