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 | 1 |
| 2 | 9 |
| 3 | 46 |
| 4 | 180 |
| 5 | 603 |
| 6 | 1827 |
| 7 | 5164 |
| 8 | 13878 |
| 9 | 35905 |
| 10 | 90189 |
| 11 | 221274 |
| 12 | 532584 |
| 13 | 1261687 |
| 14 | 2949255 |
| 15 | 6815896 |
| 16 | 15597738 |
| 17 | 35389629 |
| 18 | 79691985 |
| 19 | 178258150 |
| 20 | 396361980 |
| 21 | 876609811 |
| 22 | 1929380139 |
| 23 | 4227858756 |
| 24 | 9227469150 |
| 25 | 20065550713 |
| 26 | 43486544277 |
| 27 | 93952410034 |
| 28 | 202400334288 |