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| n | a(n) |
|---|---|
| 9 | 1 |
| 10 | 0 |
| 11 | 55 |
| 12 | 220 |
| 13 | 2860 |
| 14 | 22022 |
| 15 | 205205 |
| 16 | 1853280 |
| 17 | 17381650 |
| 18 | 200982925 |
| 19 | 2291851991 |
| 20 | 23049864630 |
| 21 | 262234646310 |
| 22 | 3319690300850 |
| 23 | 39333605649855 |
| 24 | 464026283957060 |
| 25 | 5880153732068000 |
| 26 | 75836425964702975 |
| 27 | 973764622911909400 |
| 28 | 12796285021434965050 |
| 29 | 173456578124336807300 |
[1,0,55,220,2860,22022,205205,1853280,17381650, 200982925,2291851991,23049864630,262234646310, 3319690300850,39333605649855,464026283957060, 5880153732068000,75836425964702975, 973764622911909400,12796285021434965050, 173456578124336807300] |