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 | 2 |
| 5 | 0 |
| 6 | 20 |
| 7 | 56 |
| 8 | 114 |
| 9 | 248 |
| 10 | 106 |
| 11 | 1016 |
| 12 | 1992 |
| 13 | 4016 |
| 14 | 6506 |
| 15 | 7518 |
| 16 | 24496 |
| 17 | 50358 |
| 18 | 121610 |
| 19 | 261206 |
| 20 | 483160 |