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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 130 |
| 5 | 1210 |
| 6 | 33880 |
| 7 | 925771 |
| 8 | 75913222 |
| 9 | 6174066262 |
| 10 | 1506472167928 |
| 11 | 366573514642546 |
| 12 | 267598665689058580 |
| 13 | 195168545232713290660 |
| 14 | 427028776969176679964080 |
| 15 | 934054234760012359481199283 |
| 16 | 6129263888495201102915629695046 |
[1,1,4,13,130,1210,33880,925771,75913222, 6174066262,1506472167928,366573514642546, 267598665689058580,195168545232713290660, 427028776969176679964080, 934054234760012359481199283, 6129263888495201102915629695046] |