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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 16 |
| 4 | 106 |
| 5 | 1576 |
| 6 | 1576 |
| 7 | 421996 |
| 8 | 932506 |
| 9 | 68830336 |
| 10 | 1407387556 |
| 11 | 189028491226 |
| 12 | 2996875353046 |
| 13 | 277564186341016 |
| 14 | 10013572619211736 |
| 15 | 507158503222672876 |
| 16 | 25102749806762329276 |
| 17 | 285816017624282687116 |
| 18 | 36818262670554322829446 |
| 19 | 5783948949281495901009676 |
[0,4,16,106,1576,1576,421996,932506,68830336, 1407387556,189028491226,2996875353046, 277564186341016,10013572619211736, 507158503222672876,25102749806762329276, 285816017624282687116,36818262670554322829446, 5783948949281495901009676] |