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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 6 |
| 6 | 28 |
| 7 | 82 |
| 8 | 310 |
| 9 | 918 |
| 10 | 3246 |
| 11 | 9762 |
| 12 | 33586 |
| 13 | 102490 |
| 14 | 348220 |
| 15 | 1076238 |
| 16 | 3635050 |
| 17 | 11358178 |
| 18 | 38261430 |
| 19 | 120676406 |
| 20 | 406137648 |
| 21 | 1291309912 |
| 22 | 4345989212 |
| 23 | 13914717064 |
| 24 | 46856195890 |