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 | 84 |
| 2 | 2184 |
| 3 | 30576 |
| 4 | 286650 |
| 5 | 2018016 |
| 6 | 11435424 |
| 7 | 54609984 |
| 8 | 226972746 |
| 9 | 840639800 |
| 10 | 2824549728 |
| 11 | 8730426432 |
| 12 | 25099975992 |
| 13 | 67725379008 |
| 14 | 172768824000 |
| 15 | 419252346240 |
| 16 | 972796459635 |
| 17 | 2167754048460 |
| 18 | 4656656844840 |
| 19 | 9674494830000 |
| 20 | 19494107082450 |
| 21 | 38192536324800 |
| 22 | 72913023892800 |