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 | 3 |
| 4 | 8 |
| 5 | 35 |
| 6 | 84 |
| 7 | 364 |
| 8 | 832 |
| 9 | 2997 |
| 10 | 8700 |
| 11 | 28281 |
| 12 | 55080 |
| 13 | 265720 |
| 14 | 794304 |
| 15 | 2006730 |
| 16 | 5240928 |
| 17 | 21511647 |
| 18 | 47028492 |
| 19 | 193587884 |
| 20 | 415388400 |
| 21 | 1607804226 |