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 | 16 |
| 4 | 96 |
| 5 | 624 |
| 6 | 4304 |
| 7 | 31056 |
| 8 | 232128 |
| 9 | 1784752 |
| 10 | 14043312 |
| 11 | 112648848 |
| 12 | 918456608 |
| 13 | 7593649392 |
| 14 | 63546379152 |
| 15 | 537427956688 |
| 16 | 4587713701248 |
| 17 | 39488179213872 |
| 18 | 342414691125104 |
| 19 | 2989022121125136 |
| 20 | 26249475365186016 |
| 21 | 231786459869636464 |
| 22 | 2056950693208881744 |