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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 28 |
| 6 | 116 |
| 7 | 484 |
| 8 | 2022 |
| 9 | 8448 |
| 10 | 35290 |
| 11 | 147376 |
| 12 | 615228 |
| 13 | 2567060 |
| 14 | 10704976 |
| 15 | 44611804 |
| 16 | 185780308 |
| 17 | 773060804 |
| 18 | 3214225836 |
| 19 | 13352979316 |
| 20 | 55426067494 |
| 21 | 229870371888 |
| 22 | 952548347122 |
| 23 | 3943943111920 |
| 24 | 16316243701350 |
| 25 | 67447113649312 |
| 26 | 278592165886198 |
| 27 | 1149863118820584 |
| 28 | 4742473257979906 |
| 29 | 19545876370622104 |
| 30 | 80502059920697442 |