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 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 95 |
| 6 | 848 |
| 7 | 11043 |
| 8 | 227978 |
| 9 | 7915413 |
| 10 | 482871723 |
| 11 | 52989880632 |
| 12 | 10588770680260 |
| 13 | 3880844130502271 |
| 14 | 2623179650433475894 |
| 15 | 3285998146525888516756 |
| 16 | 7663037181052161495721168 |
| 17 | 33407697920116540678510839469 |
| 18 | 273327584706334343769636571729201 |