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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 12 |
| 4 | 162 |
| 5 | 3010 |
| 6 | 81000 |
| 7 | 3105396 |
| 8 | 162469104 |
| 9 | 11117235312 |
| 10 | 961808277600 |
| 11 | 102496397652000 |
| 12 | 13180200302839680 |
| 13 | 2011319092988899200 |
| 14 | 359224661189539192320 |
| 15 | 74214101648670824736000 |
| 16 | 17557926151618710547200000 |
| 17 | 4715558231100365363023411200 |