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 | 4 |
| 3 | 14 |
| 4 | 70 |
| 5 | 454 |
| 6 | 4552 |
| 7 | 74168 |
| 8 | 2129348 |
| 9 | 111535148 |
| 10 | 10812483376 |
| 11 | 1945437208224 |
| 12 | 650378721156736 |
| 13 | 404749938336404704 |
| 14 | 470163239887698967104 |
| 15 | 1022592854829028311090816 |
| 16 | 4177826139658552046627175072 |
| 17 | 32163829440870460348768023969632 |