| n | a(n) |
|---|---|
| -1 | 1 |
| 0 | 4 |
| 1 | 276 |
| 2 | 2048 |
| 3 | 11202 |
| 4 | 49152 |
| 5 | 184024 |
| 6 | 614400 |
| 7 | 1881471 |
| 8 | 5373952 |
| 9 | 14478180 |
| 10 | 37122048 |
| 11 | 91231550 |
| 12 | 216072192 |
| 13 | 495248952 |
| 14 | 1102430208 |
| 15 | 2390434947 |
| 16 | 5061476352 |
| 17 | 10487167336 |
| 18 | 21301241856 |
| 19 | 42481784514 |
| 20 | 83300614144 |
| 21 | 160791890304 |
[1,4,276,2048,11202,49152,184024,614400,1881471, 5373952,14478180,37122048,91231550,216072192, 495248952,1102430208,2390434947,5061476352, 10487167336,21301241856,42481784514,83300614144, 160791890304] |