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 | 6 |
| 3 | 20 |
| 4 | 64 |
| 5 | 192 |
| 6 | 544 |
| 7 | 1472 |
| 8 | 3840 |
| 9 | 9728 |
| 10 | 24064 |
| 11 | 58368 |
| 12 | 139264 |
| 13 | 327680 |
| 14 | 761856 |
| 15 | 1753088 |
| 16 | 3997696 |
| 17 | 9043968 |
| 18 | 20316160 |
| 19 | 45350912 |
| 20 | 100663296 |
| 21 | 222298112 |
| 22 | 488636416 |
| 23 | 1069547520 |
| 24 | 2332033024 |
| 25 | 5066719232 |
| 26 | 10972299264 |
| 27 | 23689428992 |