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 | 3 |
| 2 | 8 |
| 3 | 18 |
| 4 | 42 |
| 5 | 90 |
| 6 | 204 |
| 7 | 432 |
| 8 | 972 |
| 9 | 2052 |
| 10 | 4610 |
| 11 | 9726 |
| 12 | 21859 |
| 13 | 46125 |
| 14 | 103783 |
| 15 | 219099 |
| 16 | 493699 |
| 17 | 1042899 |
| 18 | 2353716 |
| 19 | 4975350 |
| 20 | 11247138 |
| 21 | 23790714 |
| 22 | 53867343 |
| 23 | 114020601 |
| 24 | 258571256 |
| 25 | 547672566 |
| 26 | 1243848888 |
| 27 | 2636201532 |
| 28 | 5995717860 |