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 | 1 |
| 4 | 5 |
| 5 | 11 |
| 6 | 34 |
| 7 | 92 |
| 8 | 265 |
| 9 | 751 |
| 10 | 2156 |
| 11 | 6194 |
| 12 | 17874 |
| 13 | 51702 |
| 14 | 149941 |
| 15 | 435749 |
| 16 | 1268761 |
| 17 | 3700391 |
| 18 | 10808548 |
| 19 | 31613474 |
| 20 | 92577784 |
| 21 | 271407896 |
| 22 | 796484503 |
| 23 | 2339561795 |
| 24 | 6877992334 |
| 25 | 20236257626 |
| 26 | 59581937299 |
| 27 | 175546527727 |
| 28 | 517538571125 |
| 29 | 1526679067331 |
| 30 | 4505996000730 |