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 | 5 |
| 4 | 36 |
| 5 | 313 |
| 6 | 3904 |
| 7 | 58825 |
| 8 | 1048640 |
| 9 | 21523361 |
| 10 | 500000256 |
| 11 | 12968712301 |
| 12 | 371504186368 |
| 13 | 11649042561241 |
| 14 | 396857386631168 |
| 15 | 14596463012695313 |
| 16 | 576460752303439872 |
| 17 | 24330595937833434241 |
| 18 | 1092955779869348331520 |
| 19 | 52063675148955620766421 |
| 20 | 2621440000000000000262144 |