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 | 3 |
| 3 | 11 |
| 4 | 43 |
| 5 | 555 |
| 6 | 2603 |
| 7 | 35371 |
| 8 | 166443 |
| 9 | 2263595 |
| 10 | 136481323 |
| 11 | 673352235 |
| 12 | 35033090603 |
| 13 | 584788904491 |
| 14 | 2783812160043 |
| 15 | 37968184248875 |
| 16 | 2289767997934123 |
| 17 | 146404956073789995 |
| 18 | 722865708377213483 |
| 19 | 37616353855796316715 |
| 20 | 627912164214501968427 |
| 21 | 2989095405649324575275 |