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 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 8 |
| 7 | 20 |
| 8 | 60 |
| 9 | 148 |
| 10 | 402 |
| 11 | 986 |
| 12 | 2474 |
| 13 | 5918 |
| 14 | 14496 |
| 15 | 34708 |
| 16 | 84282 |
| 17 | 202664 |
| 18 | 492048 |