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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 37 |
| 2 | 180 |
| 3 | 640 |
| 4 | 1876 |
| 5 | 4809 |
| 6 | 11152 |
| 7 | 23905 |
| 8 | 48070 |
| 9 | 91652 |
| 10 | 167024 |
| 11 | 292747 |
| 12 | 495950 |
| 13 | 815390 |
| 14 | 1305328 |
| 15 | 2040374 |
| 16 | 3121472 |
| 17 | 4683215 |
| 18 | 6902700 |
| 19 | 10010154 |
| 20 | 14301584 |
| 21 | 20153727 |
| 22 | 28041600 |
| 23 | 38558975 |
| 24 | 52442130 |
[4,37,180,640,1876,4809,11152,23905,48070,91652, 167024,292747,495950,815390,1305328,2040374, 3121472,4683215,6902700,10010154,14301584, 20153727,28041600,38558975,52442130] |