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 | 4 |
| 4 | 6 |
| 5 | 12 |
| 6 | 36 |
| 7 | 132 |
| 8 | 144 |
| 9 | 156 |
| 10 | 900 |
| 11 | 3600 |
| 12 | 4032 |
| 13 | 7140 |
| 14 | 18360 |
| 15 | 44100 |
| 16 | 46440 |
| 17 | 4062240 |
| 18 | 9147600 |
| 19 | 999999000000 |