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 | 5 |
| 2 | 18 |
| 3 | 62 |
| 4 | 212 |
| 5 | 724 |
| 6 | 2472 |
| 7 | 8440 |
| 8 | 28816 |
| 9 | 98384 |
| 10 | 335904 |
| 11 | 1146848 |
| 12 | 3915584 |
| 13 | 13368640 |
| 14 | 45643392 |
| 15 | 155836288 |
| 16 | 532058368 |
| 17 | 1816560896 |
| 18 | 6202126848 |
| 19 | 21175385600 |
| 20 | 72297288704 |
| 21 | 246838383616 |
| 22 | 842758957056 |
| 23 | 2877359060992 |