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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 82 |
| 5 | 1599 |
| 6 | 20256 |
| 7 | 217361 |
| 8 | 2130206 |
| 9 | 19642211 |
| 10 | 173364188 |
| 11 | 1480679925 |
| 12 | 12326158938 |
| 13 | 100519162375 |
| 14 | 805975115800 |
| 15 | 6371588959001 |
| 16 | 49768503975062 |
| 17 | 384745225377195 |
| 18 | 2947749198113620 |
| 19 | 22407054537298493 |
| 20 | 169141844731289554 |
[0,0,1,82,1599,20256,217361,2130206,19642211, 173364188,1480679925,12326158938,100519162375, 805975115800,6371588959001,49768503975062, 384745225377195,2947749198113620, 22407054537298493,169141844731289554] |