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 | 1 |
| 2 | 11 |
| 3 | 89 |
| 4 | 794 |
| 5 | 6994 |
| 6 | 72204 |
| 7 | 753108 |
| 8 | 8973264 |
| 9 | 111281616 |
| 10 | 1524322080 |
| 11 | 21601104480 |
| 12 | 340803192960 |
| 13 | 5483287025280 |
| 14 | 96044874750720 |
| 15 | 1748238132614400 |
| 16 | 34093033838438400 |
| 17 | 682396164763084800 |
| 18 | 14706429413353574400 |
| 19 | 323342442475011993600 |
| 20 | 7585740483060676608000 |