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 | 3 |
| 3 | 13 |
| 4 | 87 |
| 5 | 881 |
| 6 | 13983 |
| 7 | 358401 |
| 8 | 15066943 |
| 9 | 1031686513 |
| 10 | 113292940383 |
| 11 | 19641727327289 |
| 12 | 5313784519456383 |
| 13 | 2223596389445643993 |
| 14 | 1429685952797008548463 |
| 15 | 1404762001155914382481537 |
| 16 | 2099828629077697954958843007 |