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) |
|---|---|
| 1 | 0 |
| 2 | 5 |
| 3 | 30 |
| 4 | 175 |
| 5 | 1020 |
| 6 | 5945 |
| 7 | 34650 |
| 8 | 201955 |
| 9 | 1177080 |
| 10 | 6860525 |
| 11 | 39986070 |
| 12 | 233055895 |
| 13 | 1358349300 |
| 14 | 7917039905 |
| 15 | 46143890130 |
| 16 | 268946300875 |
| 17 | 1567533915120 |
| 18 | 9136257189845 |
| 19 | 53250009223950 |
| 20 | 310363798153855 |
| 21 | 1808932779699180 |
| 22 | 10543232880041225 |
| 23 | 61450464500548170 |