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 | 2 |
| 3 | 9 |
| 4 | 44 |
| 5 | 700 |
| 6 | 7224 |
| 7 | 91728 |
| 8 | 1384704 |
| 9 | 321681456 |
| 10 | 9607635360 |
| 11 | 309488747040 |
| 12 | 10962174026880 |
| 13 | 422888522509440 |
| 14 | 17631921963720960 |
| 15 | 789561144589190400 |
| 16 | 37775032089229209600 |
| 17 | 97401432766454375731200 |
| 18 | 6978149921526727832985600 |
| 19 | 528364219172258186674790400 |