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 | 2 |
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 64 |
| 5 | 321 |
| 6 | 1927 |
| 7 | 13490 |
| 8 | 107921 |
| 9 | 971290 |
| 10 | 9712901 |
| 11 | 106841912 |
| 12 | 1282102945 |
| 13 | 16667338286 |
| 14 | 233342736005 |
| 15 | 3500141040076 |
| 16 | 56002256641217 |
| 17 | 952038362900690 |
| 18 | 17136690532212421 |
| 19 | 325597120112036000 |
| 20 | 6511942402240720001 |
| 21 | 136750790447055120022 |
| 22 | 3008517389835212640485 |