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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 49 |
| 4 | 820 |
| 5 | 21076 |
| 6 | 773136 |
| 7 | 38402064 |
| 8 | 2483133696 |
| 9 | 202759531776 |
| 10 | 20407635072000 |
| 11 | 2482492033152000 |
| 12 | 359072203696128000 |
| 13 | 60912644957448192000 |
| 14 | 11977654199703478272000 |
| 15 | 2702572249389834608640000 |