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 | 24 |
| 3 | 168 |
| 4 | 1680 |
| 5 | 23520 |
| 6 | 493920 |
| 7 | 15805440 |
| 8 | 790272000 |
| 9 | 62431488000 |
| 10 | 7866367488000 |
| 11 | 1589006232576000 |
| 12 | 516427025587200000 |
| 13 | 270607761407692800000 |
| 14 | 228934166150908108800000 |
| 15 | 312953005128291384729600000 |
| 16 | 691626141333523960252416000000 |