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 | 4 |
| 3 | 15 |
| 4 | 52 |
| 5 | 173 |
| 6 | 560 |
| 7 | 1779 |
| 8 | 5576 |
| 9 | 17305 |
| 10 | 53308 |
| 11 | 163287 |
| 12 | 497980 |
| 13 | 1513541 |
| 14 | 4587944 |
| 15 | 13878075 |
| 16 | 41910032 |
| 17 | 126395953 |
| 18 | 380795380 |
| 19 | 1146267039 |
| 20 | 3448170436 |
| 21 | 10367130845 |
| 22 | 31156000928 |
| 23 | 93599839107 |
| 24 | 281117798360 |
| 25 | 844121793481 |