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 | 27 |
| 4 | 103 |
| 5 | 501 |
| 6 | 2139 |
| 7 | 10792 |
| 8 | 49236 |
| 9 | 254818 |
| 10 | 1216292 |
| 11 | 6413110 |
| 12 | 31636466 |
| 13 | 169144070 |
| 14 | 855396960 |
| 15 | 4622049129 |
| 16 | 23826659677 |
| 17 | 129808799035 |
| 18 | 679300244477 |
| 19 | 3725129805623 |
| 20 | 19729309518411 |
| 21 | 108766381583871 |
| 22 | 581694364620265 |
| 23 | 3220950106534343 |
| 24 | 17364753783310851 |