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 | 11 |
| 3 | 52 |
| 4 | 301 |
| 5 | 2055 |
| 6 | 16139 |
| 7 | 143196 |
| 8 | 1415821 |
| 9 | 15430835 |
| 10 | 183754199 |
| 11 | 2373373752 |
| 12 | 33043478329 |
| 13 | 493278801183 |
| 14 | 7859417340599 |
| 15 | 133116815989000 |
| 16 | 2388243270461401 |
| 17 | 45243505322777619 |
| 18 | 902481863185090979 |