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 | 7 |
| 4 | 70 |
| 5 | 410 |
| 6 | 2986 |
| 7 | 20205 |
| 8 | 141313 |
| 9 | 986376 |
| 10 | 6925085 |
| 11 | 48597819 |
| 12 | 341209889 |
| 13 | 2395331138 |
| 14 | 16816717757 |
| 15 | 118065063145 |
| 16 | 828920971395 |
| 17 | 5819799452720 |
| 18 | 40860590480721 |
| 19 | 286880736650848 |
| 20 | 2014179680712444 |
| 21 | 14141486042579555 |