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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 66 |
| 5 | 2278 |
| 6 | 2598060 |
| 7 | 3374961778891 |
| 8 | 5695183504492614029263278 |
| 9 | 16217557574922386301420536972254869595782763547560 |