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) |
|---|---|
| 3 | 5 |
| 4 | 8 |
| 5 | 26 |
| 6 | 112 |
| 7 | 596 |
| 8 | 3768 |
| 9 | 27576 |
| 10 | 229248 |
| 11 | 2133792 |
| 12 | 21983040 |
| 13 | 248345280 |
| 14 | 3052719360 |
| 15 | 40563521280 |
| 16 | 579385336320 |
| 17 | 8852682585600 |
| 18 | 144083913523200 |
| 19 | 2488656760934400 |
| 20 | 45465350973235200 |
| 21 | 875935041046732800 |
| 22 | 17749186274340864000 |
| 23 | 377355425576693760000 |