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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 12 |
| 6 | 102 |
| 7 | 770 |
| 8 | 5545 |
| 9 | 39220 |
| 10 | 276144 |
| 11 | 1948212 |
| 12 | 13817680 |
| 13 | 98679990 |
| 14 | 710108396 |
| 15 | 5150076076 |
| 16 | 37641647410 |
| 17 | 277202062666 |
| 18 | 2056218941678 |
| 19 | 15358296210724 |
| 20 | 115469557503753 |
| 21 | 873561194459596 |
| 22 | 6647760790457218 |
| 23 | 50871527629923754 |
| 24 | 391345137795371013 |
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