| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 20 |
| 3 | 24 |
| 4 | 76 |
| 5 | 96 |
| 6 | 544 |
| 7 | 560 |
| 8 | 1124 |
| 9 | 1760 |
| 10 | 5056 |
| 11 | 6104 |
| 12 | 9680 |
| 13 | 31416 |
| 14 | 84640 |
| 15 | 281244 |
| 16 | 301056 |
| 17 | 585044 |
| 18 | 809716 |
| 19 | 858640 |
| 20 | 1016600 |
| 21 | 1376256 |
| 22 | 2584480 |
[4,20,24,76,96,544,560,1124,1760,5056,6104,9680, 31416,84640,281244,301056,585044,809716,858640, 1016600,1376256,2584480] |