This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 16 |
| 3 | 4128 |
| 4 | 1065008 |
| 5 | 274767936 |
| 6 | 70889062480 |
| 7 | 18289103351904 |
| 8 | 4718517775728752 |
| 9 | 1217359297034666112 |
| 10 | 314073980117168128144 |
| 11 | 81029869510932342395040 |
| 12 | 20905392259840427169792176 |