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 | 3 |
| 3 | 6 |
| 4 | 12 |
| 5 | 27 |
| 6 | 66 |
| 7 | 168 |
| 8 | 435 |
| 9 | 1134 |
| 10 | 2964 |
| 11 | 7755 |
| 12 | 20298 |
| 13 | 53136 |
| 14 | 139107 |
| 15 | 364182 |
| 16 | 953436 |
| 17 | 2496123 |
| 18 | 6534930 |
| 19 | 17108664 |
| 20 | 44791059 |
| 21 | 117264510 |
| 22 | 307002468 |
| 23 | 803742891 |
| 24 | 2104226202 |
| 25 | 5508935712 |
| 26 | 14422580931 |
| 27 | 37758807078 |
| 28 | 98853840300 |
| 29 | 258802713819 |
| 30 | 677554301154 |