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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 12 |
| 5 | 59 |
| 6 | 340 |
| 7 | 2240 |
| 8 | 16583 |
| 9 | 136185 |
| 10 | 1229220 |
| 11 | 12119025 |
| 12 | 129957670 |
| 13 | 1510458859 |
| 14 | 18958901987 |
| 15 | 255980593558 |
| 16 | 3703327622812 |
| 17 | 57208927916093 |
| 18 | 941005426734340 |
| 19 | 16442518936115083 |
| 20 | 304566619900207724 |
| 21 | 5967901050385272977 |
| 22 | 123436972340208737237 |
| 23 | 2689201938559338920299 |
[1,1,3,12,59,340,2240,16583,136185,1229220, 12119025,129957670,1510458859,18958901987, 255980593558,3703327622812,57208927916093, 941005426734340,16442518936115083, 304566619900207724,5967901050385272977, 123436972340208737237,2689201938559338920299] |