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 | 6 |
| 3 | 25 |
| 4 | 102 |
| 5 | 409 |
| 6 | 1638 |
| 7 | 6553 |
| 8 | 26214 |
| 9 | 104857 |
| 10 | 419430 |
| 11 | 1677721 |
| 12 | 6710886 |
| 13 | 26843545 |
| 14 | 107374182 |
| 15 | 429496729 |
| 16 | 1717986918 |
| 17 | 6871947673 |
| 18 | 27487790694 |
| 19 | 109951162777 |
| 20 | 439804651110 |
| 21 | 1759218604441 |
| 22 | 7036874417766 |
| 23 | 28147497671065 |