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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 3 |
| 4 | 52 |
| 5 | 305 |
| 6 | 4866 |
| 7 | 57337 |
| 8 | 1048776 |
| 9 | 18547713 |
| 10 | 407900710 |
| 11 | 9436057961 |
| 12 | 248501026236 |
| 13 | 7021087254337 |
| 14 | 217488458525898 |
| 15 | 7223642070331065 |
| 16 | 258233053457437456 |
| 17 | 9841074705853124609 |
| 18 | 399304906991091898830 |
| 19 | 17163110041947804495817 |
| 20 | 779646387683354742170820 |
[1,0,2,3,52,305,4866,57337,1048776,18547713, 407900710,9436057961,248501026236,7021087254337, 217488458525898,7223642070331065, 258233053457437456,9841074705853124609, 399304906991091898830,17163110041947804495817, 779646387683354742170820] |