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) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 40 |
| 3 | 640 |
| 4 | 14080 |
| 5 | 394240 |
| 6 | 13404160 |
| 7 | 536166400 |
| 8 | 24663654400 |
| 9 | 1282510028800 |
| 10 | 74385581670400 |
| 11 | 4760677226905600 |
| 12 | 333247405883392000 |
| 13 | 25326802847137792000 |
| 14 | 2076797833465298944000 |
| 15 | 182758209344946307072000 |
| 16 | 17179271678424952864768000 |
| 17 | 1717927167842495286476800000 |