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 | 1 |
| 2 | 4 |
| 3 | 27 |
| 4 | 255 |
| 5 | 3028 |
| 6 | 41979 |
| 7 | 647790 |
| 8 | 10803237 |
| 9 | 191122140 |
| 10 | 3542732908 |
| 11 | 68213661464 |
| 12 | 1355643940248 |
| 13 | 27673150807344 |
| 14 | 578051855658450 |
| 15 | 12318499151821116 |
| 16 | 267156147212406393 |
| 17 | 5884501351433388108 |
| 18 | 131418738987996420708 |
| 19 | 2971588663914996425000 |