| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 64 |
| 3 | 1274 |
| 4 | 21760 |
| 5 | 348722 |
| 6 | 5422144 |
| 7 | 83000234 |
| 8 | 1259729920 |
| 9 | 19027002722 |
| 10 | 286576949824 |
| 11 | 4309163074394 |
| 12 | 64731832372480 |
| 13 | 971825991711122 |
| 14 | 14585021567101504 |
| 15 | 218843984372767754 |
| 16 | 3283277591489597440 |
| 17 | 49254723695591689922 |
| 18 | 738870890792896773184 |
| 19 | 11083513664870504400314 |
[0,2,64,1274,21760,348722,5422144,83000234, 1259729920,19027002722,286576949824,4309163074394, 64731832372480,971825991711122,14585021567101504, 218843984372767754,3283277591489597440, 49254723695591689922,738870890792896773184, 11083513664870504400314] |