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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 4 |
| 4 | 14 |
| 5 | 156 |
| 6 | 20 |
| 7 | 750 |
| 8 | 1763 |
| 9 | 22142 |
| 10 | 77776 |
| 11 | 64420 |
| 12 | 2443077 |
| 13 | 52663933 |
| 14 | 227623468 |
| 15 | 1097568095 |
| 16 | 3149642939 |
| 17 | 81965144711 |
| 18 | 105625962315 |
| 19 | 143416754568 |
| 20 | 8084207326294 |
| 21 | 2574579252942508 |
| 22 | 14079288482520493 |
| 23 | 68732231173154643 |
| 24 | 33344665050312525 |
| 25 | 350798169613138819009 |
| 26 | 201175550741393337488 |
[1,4,14,156,20,750,1763,22142,77776,64420,2443077, 52663933,227623468,1097568095,3149642939, 81965144711,105625962315,143416754568, 8084207326294,2574579252942508,14079288482520493, 68732231173154643,33344665050312525, 350798169613138819009,201175550741393337488] |