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 | 1 |
| 3 | 2 |
| 4 | 12 |
| 5 | 146 |
| 6 | 5847 |
| 7 | 716141 |
| 8 | 300635753 |
| 9 | 430472002801 |
| 10 | 2117649544384420 |
| 11 | 36154420408979339192 |
| 12 | 2165755991529764630384554 |
| 13 | 459803603042851200545393118005 |