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 | 2 |
| 3 | 8 |
| 4 | 50 |
| 5 | 436 |
| 6 | 4912 |
| 7 | 68098 |
| 8 | 1122952 |
| 9 | 21488640 |
| 10 | 468331252 |
| 11 | 11456367820 |
| 12 | 310888085872 |
| 13 | 9269621420284 |
| 14 | 301268634277760 |
| 15 | 10601062978739338 |
| 16 | 401550210033474420 |
| 17 | 16291237867482727084 |
| 18 | 704847239600911931248 |