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 | 0 |
| 2 | 1 |
| 3 | 6 |
| 4 | 81 |
| 5 | 80 |
| 6 | 56 |
| 7 | 7284 |
| 8 | 33889 |
| 9 | 2044921 |
| 10 | 8151937 |
| 11 | 127668791 |
| 12 | 258943304 |
| 13 | 19207561921 |
| 14 | 189815680859 |
| 15 | 2687562198191 |
| 16 | 75909586168557 |
| 17 | 512148453482307 |
| 18 | 5376323935222903 |
| 19 | 502774568129731130 |
| 20 | 1053338431686717460 |
| 21 | 122114339415457901831 |
| 22 | 2120280158164651048122 |