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 | 1 |
| 2 | 3 |
| 3 | 19 |
| 4 | 221 |
| 5 | 4597 |
| 6 | 174007 |
| 7 | 12328367 |
| 8 | 1674839513 |
| 9 | 443624694633 |
| 10 | 231531387336683 |
| 11 | 239620527240665643 |
| 12 | 493608618766634690997 |
| 13 | 2028225390820399637729437 |
| 14 | 16643586506902581140427736799 |
| 15 | 272938023130910288846692573380167 |
| 16 | 8947998686305041917555662919172783921 |