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 | 4 |
| 2 | 9 |
| 3 | 21 |
| 4 | 49 |
| 5 | 113 |
| 6 | 257 |
| 7 | 577 |
| 8 | 1281 |
| 9 | 2817 |
| 10 | 6145 |
| 11 | 13313 |
| 12 | 28673 |
| 13 | 61441 |
| 14 | 131073 |
| 15 | 278529 |
| 16 | 589825 |
| 17 | 1245185 |
| 18 | 2621441 |
| 19 | 5505025 |
| 20 | 11534337 |
| 21 | 24117249 |
| 22 | 50331649 |
| 23 | 104857601 |
| 24 | 218103809 |
| 25 | 452984833 |
| 26 | 939524097 |
| 27 | 1946157057 |
| 28 | 4026531841 |