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 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 5 |
| 7 | 20 |
| 8 | 55 |
| 9 | 125 |
| 10 | 251 |
| 11 | 2300 |
| 12 | 15775 |
| 13 | 70500 |
| 14 | 249250 |
| 15 | 750751 |
| 16 | 10006375 |
| 17 | 97226875 |
| 18 | 601638125 |
| 19 | 2886735625 |
| 20 | 11593285251 |
| 21 | 202808749375 |
| 22 | 2550175096250 |
| 23 | 20163891580625 |
| 24 | 122209131374375 |
| 25 | 613498040952501 |
| 26 | 13287626090593750 |
| 27 | 205055676105734375 |