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 | 5 |
| 3 | 27 |
| 4 | 161 |
| 5 | 1030 |
| 6 | 6921 |
| 7 | 48190 |
| 8 | 344669 |
| 9 | 2517303 |
| 10 | 18695908 |
| 11 | 140771477 |
| 12 | 1072130229 |
| 13 | 8244820518 |
| 14 | 63931532190 |
| 15 | 499308229278 |
| 16 | 3924204043333 |
| 17 | 31012883225891 |
| 18 | 246304580923299 |
| 19 | 1964794017165157 |
| 20 | 15735626383151876 |
| 21 | 126476316316459089 |
| 22 | 1019883740031357941 |