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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 12 |
| 7 | 72 |
| 8 | 352 |
| 9 | 1472 |
| 10 | 5756 |
| 11 | 26336 |
| 12 | 180116 |
| 13 | 1577006 |
| 14 | 13720566 |
| 15 | 109776526 |
| 16 | 829240726 |
| 17 | 6488348726 |
| 18 | 59134377126 |
| 19 | 640605185526 |
| 20 | 7502207070150 |
| 21 | 87309498759810 |
| 22 | 989782736128170 |
| 23 | 11277397727184650 |
| 24 | 136523328121058170 |
| 25 | 1817775858886701082 |
[1,1,1,1,1,2,12,72,352,1472,5756,26336,180116, 1577006,13720566,109776526,829240726,6488348726, 59134377126,640605185526,7502207070150, 87309498759810,989782736128170,11277397727184650, 136523328121058170,1817775858886701082] |