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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 28 |
| 4 | 272 |
| 5 | 3126 |
| 6 | 47450 |
| 7 | 823544 |
| 8 | 16842752 |
| 9 | 387440172 |
| 10 | 10009766650 |
| 11 | 285311670612 |
| 12 | 8918294011904 |
| 13 | 302875106592254 |
| 14 | 11112685048647250 |
| 15 | 437893920912786408 |
| 16 | 18447025548686262272 |
| 17 | 827240261886336764178 |
| 18 | 39346558271492178663450 |
| 19 | 1978419655660313589123980 |
[1,5,28,272,3126,47450,823544,16842752,387440172, 10009766650,285311670612,8918294011904, 302875106592254,11112685048647250, 437893920912786408,18447025548686262272, 827240261886336764178,39346558271492178663450, 1978419655660313589123980] |