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 | 4 |
| 1 | 10 |
| 2 | 25 |
| 3 | 63 |
| 4 | 159 |
| 5 | 402 |
| 6 | 1017 |
| 7 | 2573 |
| 8 | 6510 |
| 9 | 16472 |
| 10 | 41679 |
| 11 | 105461 |
| 12 | 266850 |
| 13 | 675216 |
| 14 | 1708513 |
| 15 | 4323086 |
| 16 | 10938795 |
| 17 | 27678662 |
| 18 | 70035898 |
| 19 | 177213300 |
| 20 | 448406526 |
| 21 | 1134612428 |
| 22 | 2870933600 |
| 23 | 7264383443 |
| 24 | 18381221638 |
| 25 | 46510390257 |
| 26 | 117686215012 |
| 27 | 297783895756 |
| 28 | 753488830979 |