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 | 2 |
| 4 | 8 |
| 5 | 32 |
| 6 | 112 |
| 7 | 394 |
| 8 | 1360 |
| 9 | 4736 |
| 10 | 16544 |
| 11 | 58324 |
| 12 | 207088 |
| 13 | 741184 |
| 14 | 2671008 |
| 15 | 9688410 |
| 16 | 35344800 |
| 17 | 129620480 |
| 18 | 477590080 |
| 19 | 1767170812 |
| 20 | 6563935664 |
| 21 | 24465914304 |
| 22 | 91481858208 |
| 23 | 343058261572 |
| 24 | 1289901443168 |