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 | 6 |
| 3 | 57 |
| 4 | 2309 |
| 5 | 292103 |
| 6 | 90647411 |
| 7 | 37593032352 |
| 8 | 16429342163157 |
| 9 | 6925787777638463 |
| 10 | 2729333815881686935 |
| 11 | 995740669987430403414 |
| 12 | 335945077218184962957540 |
| 13 | 105067580130605231781256012 |