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 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 28 |
| 5 | 128 |
| 6 | 754 |
| 7 | 5178 |
| 8 | 41124 |
| 9 | 368220 |
| 10 | 3670872 |
| 11 | 40290744 |
| 12 | 482716896 |
| 13 | 6267697920 |
| 14 | 87664818960 |
| 15 | 1313983544400 |
| 16 | 21010949076960 |
| 17 | 357007805477280 |
| 18 | 6423473819220480 |
| 19 | 122003441554176000 |
| 20 | 2439346762501367040 |
| 21 | 51213306647556506880 |
| 22 | 1126446562222595147520 |