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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 18 |
| 5 | 96 |
| 6 | 579 |
| 7 | 3834 |
| 8 | 27404 |
| 9 | 209052 |
| 10 | 1688389 |
| 11 | 14350934 |
| 12 | 127790843 |
| 13 | 1187887298 |
| 14 | 11493457661 |
| 15 | 115475260028 |
| 16 | 1202307540187 |
| 17 | 12950284520902 |
| 18 | 144086601275823 |
| 19 | 1653734575825448 |
| 20 | 19556088359856621 |
| 21 | 238010195665296028 |
| 22 | 2978302718258295407 |
| 23 | 38282183452466374942 |
| 24 | 505012097362619472074 |
[1,1,4,18,96,579,3834,27404,209052,1688389, 14350934,127790843,1187887298,11493457661, 115475260028,1202307540187,12950284520902, 144086601275823,1653734575825448, 19556088359856621,238010195665296028, 2978302718258295407,38282183452466374942, 505012097362619472074] |