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 | 4 |
| 3 | 44 |
| 4 | 2593 |
| 5 | 407620 |
| 6 | 333518324 |
| 7 | 696849783788 |
| 8 | 7561681603209033 |
| 9 | 204785162442300693673 |
| 10 | 28874426647917459828127044 |
| 11 | 10023323177854055068860282476760 |
| 12 | 18172145684566998309243670369029131178 |
| 13 | 80387219406473992671391703779030095453926416 |