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 | 2 |
| 3 | 8 |
| 4 | 24 |
| 5 | 68 |
| 6 | 188 |
| 7 | 516 |
| 8 | 1412 |
| 9 | 3860 |
| 10 | 10548 |
| 11 | 28820 |
| 12 | 78740 |
| 13 | 215124 |
| 14 | 587732 |
| 15 | 1605716 |
| 16 | 4386900 |
| 17 | 11985236 |
| 18 | 32744276 |
| 19 | 89459028 |
| 20 | 244406612 |
| 21 | 667731284 |
| 22 | 1824275796 |
| 23 | 4984014164 |
| 24 | 13616579924 |
| 25 | 37201188180 |
| 26 | 101635536212 |
| 27 | 277673448788 |
| 28 | 758617970004 |
| 29 | 2072582837588 |