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 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 35 |
| 6 | 129 |
| 7 | 495 |
| 8 | 2101 |
| 9 | 9154 |
| 10 | 41356 |
| 11 | 189466 |
| 12 | 880156 |
| 13 | 4120515 |
| 14 | 19425037 |
| 15 | 92038062 |
| 16 | 438030079 |
| 17 | 2092403558 |
| 18 | 10027947217 |
| 19 | 48198234188 |
| 20 | 232261124908 |
| 21 | 1121853426115 |
| 22 | 5430222591596 |