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 | 2 |
| 2 | 8 |
| 3 | 52 |
| 4 | 448 |
| 5 | 4848 |
| 6 | 62912 |
| 7 | 952992 |
| 8 | 16496640 |
| 9 | 321282816 |
| 10 | 6952332288 |
| 11 | 165489858048 |
| 12 | 4297340166144 |
| 13 | 120890184308736 |
| 14 | 3662409013420032 |
| 15 | 118879239686541312 |
| 16 | 4115985952586858496 |
| 17 | 151415632063102648320 |
| 18 | 5897814669785134006272 |
| 19 | 242489327746828076974080 |