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 | 88 |
| 5 | 285 |
| 6 | 882 |
| 7 | 2661 |
| 8 | 7916 |
| 9 | 23381 |
| 10 | 68850 |
| 11 | 202621 |
| 12 | 596768 |
| 13 | 1760289 |
| 14 | 5201854 |
| 15 | 15401317 |
| 16 | 45682536 |
| 17 | 135728009 |
| 18 | 403864570 |
| 19 | 1203278513 |
| 20 | 3589064828 |
| 21 | 10715405153 |
| 22 | 32017223498 |
| 23 | 95730557865 |
| 24 | 286392391568 |
| 25 | 857187336029 |