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 | -1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 9 |
| 5 | 34 |
| 6 | 130 |
| 7 | 496 |
| 8 | 1897 |
| 9 | 7274 |
| 10 | 27966 |
| 11 | 107788 |
| 12 | 416394 |
| 13 | 1611908 |
| 14 | 6251596 |
| 15 | 24287212 |
| 16 | 94499689 |
| 17 | 368202778 |
| 18 | 1436458486 |
| 19 | 5610483532 |
| 20 | 21936442894 |
| 21 | 85852554748 |
| 22 | 336300861436 |
| 23 | 1318441228432 |
| 24 | 5172792817834 |
| 25 | 20309402206084 |