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 | 1 |
| 3 | 42 |
| 4 | 15654 |
| 5 | 1073421588 |
| 6 | 4611685989440629944 |
| 7 | 85070591730234615704434641716516893512 |
| 8 | 28948022309329048855892746252171976959574390130279817915318273546782086570304 |