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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 12 |
| 5 | 60 |
| 6 | 420 |
| 7 | 4620 |
| 8 | 9240 |
| 9 | 27720 |
| 10 | 360360 |
| 11 | 6126120 |
| 12 | 116396280 |
| 13 | 2677114440 |
| 14 | 77636318760 |
| 15 | 2406725881560 |
| 16 | 4813451763120 |
| 17 | 178097715235440 |
| 18 | 7302006324653040 |
| 19 | 313986271960080720 |
| 20 | 14757354782123793840 |