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 | 4 |
| 2 | 26 |
| 3 | 181 |
| 4 | 1095 |
| 5 | 6416 |
| 6 | 35285 |
| 7 | 187929 |
| 8 | 973404 |
| 9 | 4934952 |
| 10 | 24628655 |
| 11 | 121375817 |
| 12 | 592337729 |
| 13 | 2868086641 |
| 14 | 13798982719 |
| 15 | 66043675287 |
| 16 | 314715355786 |
| 17 | 1494166794434 |
| 18 | 7071357084444 |
| 19 | 33374079939405 |