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 | 0 |
| 3 | 8 |
| 4 | 28 |
| 5 | 120 |
| 6 | 460 |
| 7 | 1848 |
| 8 | 7308 |
| 9 | 29240 |
| 10 | 116620 |
| 11 | 466488 |
| 12 | 1864588 |
| 13 | 7458360 |
| 14 | 29827980 |
| 15 | 119311928 |
| 16 | 477225868 |
| 17 | 1908903480 |
| 18 | 7635526540 |
| 19 | 30542106168 |
| 20 | 122168075148 |
| 21 | 488672300600 |
| 22 | 1954687804300 |