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 | 21 |
| 4 | 273 |
| 5 | 5733 |
| 6 | 177723 |
| 7 | 7642089 |
| 8 | 435599073 |
| 9 | 31798732329 |
| 10 | 2893684641939 |
| 11 | 321198995255229 |
| 12 | 42719466368945457 |
| 13 | 6706956219924436749 |
| 14 | 1227372988246171925067 |
| 15 | 258975700519942276189137 |
| 16 | 62413143825306088561582017 |
| 17 | 17038788264308562177311890641 |