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 | 2 |
| 3 | 6 |
| 4 | 30 |
| 5 | 210 |
| 6 | 2310 |
| 7 | 30030 |
| 8 | 510510 |
| 9 | 11741730 |
| 10 | 293543250 |
| 11 | 8512754250 |
| 12 | 314971907250 |
| 13 | 12913848197250 |
| 14 | 555295472481750 |
| 15 | 26098887206642250 |
| 16 | 1383241021952039250 |
| 17 | 84377702339074394250 |
| 18 | 5653306056717984414750 |
| 19 | 401384730026976893447250 |
| 20 | 30906624212077220795438250 |