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 | 4 |
| 3 | 15 |
| 4 | 59 |
| 5 | 243 |
| 6 | 1034 |
| 7 | 4501 |
| 8 | 19920 |
| 9 | 89281 |
| 10 | 404184 |
| 11 | 1844789 |
| 12 | 8477571 |
| 13 | 39183625 |
| 14 | 182010366 |
| 15 | 849115811 |
| 16 | 3976405347 |
| 17 | 18684473203 |
| 18 | 88060677880 |
| 19 | 416162484693 |
| 20 | 1971567963673 |
| 21 | 9361218368921 |
| 22 | 44539107835094 |
| 23 | 212308063827055 |
| 24 | 1013779444844754 |
| 25 | 4848597239921803 |