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 | 1 |
| 2 | 13 |
| 3 | 43561 |
| 4 | 455366036161 |
| 5 | 60209252317216962943201 |
| 6 | 291857679749953126623181556402787323521 |
| 7 | 120972618144269517756284629487432992029777542693069847287041 |