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 | 2 |
| 2 | 6 |
| 3 | 30 |
| 4 | 870 |
| 5 | 9570 |
| 6 | 66990 |
| 7 | 870870 |
| 8 | 32222190 |
| 9 | 547777230 |
| 10 | 43274401170 |
| 11 | 995311226910 |
| 12 | 4109640055911390 |
| 13 | 793160530790898270 |
| 14 | 2056665256340799214110 |
| 15 | 207723190890420720625110 |