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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 6 |
| 4 | 29 |
| 5 | 125 |
| 6 | 538 |
| 7 | 2282 |
| 8 | 9916 |
| 9 | 43416 |
| 10 | 195206 |
| 11 | 891638 |
| 12 | 4176002 |
| 13 | 19920914 |
| 14 | 97248184 |
| 15 | 483752596 |
| 16 | 2458123328 |
| 17 | 12722535412 |
| 18 | 67155870194 |
| 19 | 360792258750 |
| 20 | 1974047659038 |
| 21 | 10983669569446 |
| 22 | 62162472053580 |
| 23 | 357454683655920 |
| 24 | 2088497013864312 |
| 25 | 12387836332741800 |