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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 7 |
| 5 | 31 |
| 6 | 121 |
| 7 | 526 |
| 8 | 2227 |
| 9 | 9283 |
| 10 | 54931 |
| 11 | 694156 |
| 12 | 6104011 |
| 13 | 76333687 |
| 14 | 872550043 |
| 15 | 7491293356 |
| 16 | 49469173951 |
| 17 | 1571562887071 |
| 18 | 24729107440927 |
| 19 | 584036983443568 |
| 20 | 8662243014551731 |
| 21 | 87570785839885951 |
| 22 | 1147293350653737211 |
| 23 | 66175018194591458692 |
| 24 | 1378758190497550145383 |
[0,0,1,7,31,121,526,2227,9283,54931,694156, 6104011,76333687,872550043,7491293356,49469173951, 1571562887071,24729107440927,584036983443568, 8662243014551731,87570785839885951, 1147293350653737211,66175018194591458692, 1378758190497550145383] |