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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 45 |
| 4 | 560 |
| 5 | 9795 |
| 6 | 223524 |
| 7 | 6284089 |
| 8 | 210208560 |
| 9 | 8156750283 |
| 10 | 360297117070 |
| 11 | 17853149451841 |
| 12 | 980844453593160 |
| 13 | 59179098916735213 |
| 14 | 3890176308574524934 |
| 15 | 276750779199166606705 |
| 16 | 21185250061147839785120 |
| 17 | 1736385140876356212244563 |
| 18 | 151719500906542020597450498 |
[1,6,45,560,9795,223524,6284089,210208560, 8156750283,360297117070,17853149451841, 980844453593160,59179098916735213, 3890176308574524934,276750779199166606705, 21185250061147839785120,1736385140876356212244563, 151719500906542020597450498] |