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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 9 |
| 5 | 29 |
| 6 | 235 |
| 7 | 1373 |
| 8 | 12369 |
| 9 | 103385 |
| 10 | 1084371 |
| 11 | 11574289 |
| 12 | 141594233 |
| 13 | 1818356773 |
| 14 | 25656355803 |
| 15 | 382941579733 |
| 16 | 6146456787873 |
| 17 | 104279900050865 |
| 18 | 1879443080591011 |
| 19 | 35680329646116377 |
| 20 | 713976964110565065 |
| 21 | 14988564748268742269 |
| 22 | 329817773336305467819 |