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 | 39 |
| 3 | 429 |
| 4 | 5565 |
| 5 | 94605 |
| 6 | 1040655 |
| 7 | 2332655745 |
| 8 | 178516966485 |
| 9 | 4105890229155 |
| 10 | 867388559982945 |
| 11 | 37297708079266635 |
| 12 | 1529206031249932035 |