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 | 1 |
| 2 | 12 |
| 3 | 270 |
| 4 | 8960 |
| 5 | 406250 |
| 6 | 23293872 |
| 7 | 1617774592 |
| 8 | 132075970560 |
| 9 | 12397121784954 |
| 10 | 1315528361642000 |
| 11 | 155743010418063860 |
| 12 | 20351866171905066240 |
| 13 | 2909818652684404979440 |
| 14 | 451849287590990124662400 |
| 15 | 75730203998219999637000000 |
| 16 | 13625593688459657260608782336 |
| 17 | 2619521322904712777031960349850 |