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 | 4 |
| 3 | 22 |
| 4 | 52 |
| 5 | 1522 |
| 6 | 29242 |
| 7 | 299512 |
| 8 | 4383592 |
| 9 | 188677702 |
| 10 | 5765999452 |
| 11 | 5765999452 |
| 12 | 2211931390882 |
| 13 | 165468170356702 |
| 14 | 8075975022064162 |
| 15 | 361310530977154972 |
| 16 | 20037783573808880092 |
| 17 | 1779852341342071295512 |
| 18 | 40235059344426324076912 |
| 19 | 4966347076439519105374252 |
| 20 | 169991099649125127278835142 |