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 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 4 |
| 5 | 20 |
| 6 | 66 |
| 7 | 287 |
| 8 | 1296 |
| 9 | 6435 |
| 10 | 34250 |
| 11 | 194942 |
| 12 | 1179036 |
| 13 | 7544121 |
| 14 | 50865920 |
| 15 | 360167355 |
| 16 | 2670210640 |
| 17 | 20673196460 |
| 18 | 166753291806 |
| 19 | 1398415162703 |
| 20 | 12169520162440 |
| 21 | 109709590135635 |
| 22 | 1022997624845614 |
| 23 | 9852508254721222 |
| 24 | 97880299543896216 |
| 25 | 1001841501018883425 |