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 | 17 |
| 3 | 70 |
| 4 | 289 |
| 5 | 1191 |
| 6 | 4913 |
| 7 | 20256 |
| 8 | 83521 |
| 9 | 344365 |
| 10 | 1419857 |
| 11 | 5854220 |
| 12 | 24137569 |
| 13 | 99521746 |
| 14 | 410338673 |
| 15 | 1691869691 |
| 16 | 6975757441 |
| 17 | 28761784747 |
| 18 | 118587876497 |
| 19 | 488950340714 |
| 20 | 2015993900449 |
| 21 | 8312155792152 |
| 22 | 34271896307633 |
| 23 | 141306648466586 |
| 24 | 582622237229761 |
| 25 | 2402213023931974 |