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 | 6 |
| 3 | 30 |
| 4 | 210 |
| 5 | 2310 |
| 6 | 30030 |
| 7 | 690690 |
| 8 | 14804790 |
| 9 | 223092870 |
| 10 | 8254436190 |
| 11 | 200560490130 |
| 12 | 8222980095330 |
| 13 | 304250263527210 |
| 14 | 13082761331670030 |
| 15 | 614889782588491410 |
| 16 | 32589158477190044730 |
| 17 | 1987938667108592728530 |
| 18 | 117288381359406970983270 |
| 19 | 7858321551080267055879090 |