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 | 3 |
| 2 | 14 |
| 3 | 75 |
| 4 | 429 |
| 5 | 2548 |
| 6 | 15504 |
| 7 | 95931 |
| 8 | 600875 |
| 9 | 3798795 |
| 10 | 24192090 |
| 11 | 154969620 |
| 12 | 997490844 |
| 13 | 6446369400 |
| 14 | 41802112192 |
| 15 | 271861216539 |
| 16 | 1772528290407 |
| 17 | 11582393855305 |
| 18 | 75831424919250 |
| 19 | 497337483739635 |
| 20 | 3266814940064445 |