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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 20 |
| 4 | 209 |
| 5 | 3173 |
| 6 | 67292 |
| 7 | 1970761 |
| 8 | 79764057 |
| 9 | 4490097388 |
| 10 | 354111363537 |
| 11 | 39360693851404 |
| 12 | 6193012446752244 |
| 13 | 1383433132321835172 |
| 14 | 439684769985895688173 |
| 15 | 199116777197880585373014 |
| 16 | 128631139424158036273736167 |
| 17 | 118640007280899188486618513612 |
[1,1,3,20,209,3173,67292,1970761,79764057, 4490097388,354111363537,39360693851404, 6193012446752244,1383433132321835172, 439684769985895688173,199116777197880585373014, 128631139424158036273736167, 118640007280899188486618513612] |