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 | 12 |
| 3 | 91 |
| 4 | 726 |
| 5 | 5902 |
| 6 | 48704 |
| 7 | 406353 |
| 8 | 3419020 |
| 9 | 28958955 |
| 10 | 246598716 |
| 11 | 2109182557 |
| 12 | 18106771400 |
| 13 | 155929895685 |
| 14 | 1346442959176 |
| 15 | 11653675471305 |
| 16 | 101071521560286 |
| 17 | 878176794266261 |
| 18 | 7642505705447340 |
| 19 | 66606583068846975 |