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 | 0 |
| 1 | 9 |
| 2 | 126 |
| 3 | 1539 |
| 4 | 17496 |
| 5 | 190269 |
| 6 | 2007666 |
| 7 | 20726199 |
| 8 | 210450636 |
| 9 | 2109289329 |
| 10 | 20920706406 |
| 11 | 205720279659 |
| 12 | 2008387814976 |
| 13 | 19487638017189 |
| 14 | 188098071296346 |
| 15 | 1807266603941919 |
| 16 | 17294855095950516 |
| 17 | 164918796807813849 |
| 18 | 1567655079768657486 |
| 19 | 14859368894402912979 |