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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 19 |
| 4 | 65 |
| 5 | 211 |
| 6 | 665 |
| 7 | 2059 |
| 8 | 6305 |
| 9 | 19171 |
| 10 | 58025 |
| 11 | 175099 |
| 12 | 527345 |
| 13 | 1586131 |
| 14 | 4766585 |
| 15 | 14316139 |
| 16 | 42981185 |
| 17 | 129009091 |
| 18 | 387158345 |
| 19 | 1161737179 |
| 20 | 3485735825 |
| 21 | 10458256051 |
| 22 | 31376865305 |
| 23 | 94134790219 |
| 24 | 282412759265 |
| 25 | 847255055011 |
| 26 | 2541798719465 |
| 27 | 7625463267259 |
| 28 | 22876524019505 |