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 | 2 |
| 2 | 12 |
| 3 | 24 |
| 4 | 240 |
| 5 | 480 |
| 6 | 6720 |
| 7 | 13440 |
| 8 | 241920 |
| 9 | 483840 |
| 10 | 10644480 |
| 11 | 21288960 |
| 12 | 553512960 |
| 13 | 1107025920 |
| 14 | 2214051840 |
| 15 | 4428103680 |
| 16 | 150555525120 |
| 17 | 301111050240 |
| 18 | 11442219909120 |
| 19 | 22884439818240 |
| 20 | 45768879636480 |