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 | 2 |
| 3 | 7 |
| 4 | 66 |
| 5 | 3061 |
| 6 | 1095266 |
| 7 | 3906746485 |
| 8 | 165835140118904 |
| 9 | 96867653699340061187 |
| 10 | 883158060528372369857672080 |
| 11 | 140546577721904223563711600192372503 |