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 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 64 |
| 5 | 312 |
| 6 | 1812 |
| 7 | 12288 |
| 8 | 95616 |
| 9 | 840960 |
| 10 | 8254080 |
| 11 | 89441280 |
| 12 | 1060369920 |
| 13 | 13649610240 |
| 14 | 189550368000 |
| 15 | 2824077312000 |
| 16 | 44927447040000 |
| 17 | 760034451456000 |
| 18 | 13622700994560000 |
| 19 | 257872110354432000 |
| 20 | 5140559166898176000 |
| 21 | 107637093007589376000 |
| 22 | 2361827297364885504000 |