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 | 4 |
| 2 | 61 |
| 3 | 1663 |
| 4 | 243263 |
| 5 | 9857663 |
| 6 | 3982846453 |
| 7 | 122168020854499 |
| 8 | 772191321163986959 |
| 9 | 235380054470968985242897 |
| 10 | 390489415238382125919557233 |
| 11 | 2056313729049707794675149973499 |
| 12 | 18249666491214590662011175235075053 |
| 13 | 4157609603822695440999128471752421052593 |