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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 4 |
| 8 | 29 |
| 9 | 90 |
| 10 | 188 |
| 11 | 345 |
| 12 | 825 |
| 13 | 3089 |
| 14 | 13450 |
| 15 | 54526 |
| 16 | 198846 |
| 17 | 668430 |
| 18 | 2155731 |
| 19 | 6963768 |
| 20 | 23265733 |
| 21 | 81163559 |
| 22 | 292726843 |
| 23 | 1073684818 |
| 24 | 3953422052 |
| 25 | 14517741411 |
| 26 | 53096290021 |
| 27 | 193719344526 |
| 28 | 706944953011 |
| 29 | 2586796240687 |
| 30 | 9505841335788 |
| 31 | 35102295346482 |
[1,0,0,0,4,29,90,188,345,825,3089,13450,54526, 198846,668430,2155731,6963768,23265733,81163559, 292726843,1073684818,3953422052,14517741411, 53096290021,193719344526,706944953011, 2586796240687,9505841335788,35102295346482] |