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 | 2 |
| 3 | 3 |
| 4 | 8 |
| 5 | 18 |
| 6 | 43 |
| 7 | 104 |
| 8 | 273 |
| 9 | 702 |
| 10 | 1870 |
| 11 | 4985 |
| 12 | 13562 |
| 13 | 37038 |
| 14 | 102266 |
| 15 | 283774 |
| 16 | 793189 |
| 17 | 2227115 |
| 18 | 6286044 |
| 19 | 17811751 |
| 20 | 50672898 |
| 21 | 144639235 |
| 22 | 414181050 |
| 23 | 1189365940 |
| 24 | 3424477813 |
| 25 | 9883578364 |
| 26 | 28589660227 |
| 27 | 82870288432 |
| 28 | 240672107114 |