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 | 3 |
| 2 | 9 |
| 3 | 24 |
| 4 | 63 |
| 5 | 159 |
| 6 | 396 |
| 7 | 969 |
| 8 | 2349 |
| 9 | 5640 |
| 10 | 13455 |
| 11 | 31911 |
| 12 | 75348 |
| 13 | 177225 |
| 14 | 415557 |
| 15 | 971808 |
| 16 | 2267631 |
| 17 | 5281359 |
| 18 | 12280860 |
| 19 | 28518153 |
| 20 | 66147165 |
| 21 | 153274488 |
| 22 | 354861711 |
| 23 | 820976631 |
| 24 | 1898144676 |
| 25 | 4386240393 |
| 26 | 10131006069 |
| 27 | 23390390544 |
| 28 | 53984735343 |