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 | 2 |
| 2 | 9 |
| 3 | 20 |
| 4 | 89 |
| 5 | 198 |
| 6 | 881 |
| 7 | 1960 |
| 8 | 8721 |
| 9 | 19402 |
| 10 | 86329 |
| 11 | 192060 |
| 12 | 854569 |
| 13 | 1901198 |
| 14 | 8459361 |
| 15 | 18819920 |
| 16 | 83739041 |
| 17 | 186298002 |
| 18 | 828931049 |
| 19 | 1844160100 |
| 20 | 8205571449 |
| 21 | 18255302998 |
| 22 | 81226783441 |
| 23 | 180708869880 |