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 | 6 |
| 3 | 27 |
| 4 | 124 |
| 5 | 645 |
| 6 | 3906 |
| 7 | 27391 |
| 8 | 219192 |
| 9 | 1972809 |
| 10 | 19728190 |
| 11 | 217010211 |
| 12 | 2604122676 |
| 13 | 33853594957 |
| 14 | 473950329594 |
| 15 | 7109254944135 |
| 16 | 113748079106416 |
| 17 | 1933717344809361 |
| 18 | 34806912206568822 |
| 19 | 661331331924807979 |