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) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 12 |
| 4 | 44 |
| 5 | 182 |
| 6 | 796 |
| 7 | 3612 |
| 8 | 16786 |
| 9 | 79426 |
| 10 | 381250 |
| 11 | 1851832 |
| 12 | 9086022 |
| 13 | 44970688 |
| 14 | 224279188 |
| 15 | 1126038472 |
| 16 | 5687027204 |
| 17 | 28873452032 |
| 18 | 147281732692 |
| 19 | 754443210294 |