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 | 1 |
| 1 | 5 |
| 2 | 31 |
| 3 | 255 |
| 4 | 2577 |
| 5 | 31245 |
| 6 | 439695 |
| 7 | 7072695 |
| 8 | 127699425 |
| 9 | 2562270165 |
| 10 | 56484554175 |
| 11 | 1358576240175 |
| 12 | 35374065613425 |
| 13 | 992016072172125 |
| 14 | 29792674421484975 |
| 15 | 954480422711190375 |
| 16 | 32479589325536978625 |
| 17 | 1170329273010701929125 |
| 18 | 44502357662442514209375 |
| 19 | 1781390379962467540641375 |