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 | 3 |
| 5 | 15 |
| 6 | 90 |
| 7 | 630 |
| 8 | 630 |
| 9 | 210 |
| 10 | 2100 |
| 11 | 23100 |
| 12 | 34650 |
| 13 | 450450 |
| 14 | 6306300 |
| 15 | 28028 |
| 16 | 7007 |
| 17 | 119119 |
| 18 | 2144142 |
| 19 | 40738698 |
| 20 | 101846745 |
| 21 | 230945 |
| 22 | 5080790 |
| 23 | 116858170 |
| 24 | 350574510 |
| 25 | 70114902 |
| 26 | 1822987452 |
| 27 | 1822987452 |
| 28 | 6380456082 |
| 29 | 185033226378 |
| 30 | 5550996791340 |